A Sub-Trope of Comic Book Time, Long Runner, and Technology Marches On. Sister Trope to Not Allowed to Grow Up.
So you are watching early episodes of a show that is set in the Present Day, or, what was the present for when the show came out. In Real Life when these episodes were written, tech that we now take for granted was just coming out, and the show would reflect this, showing everything from CD-ROMS, the Internet, big desktop computers, cell phones, and what have you as the latest thing.
Fast forward years later in Real Life to now. The show storyline is still set at roughly the same time as the early episodes, but in order to keep up with the real world, the characters are now playing with iPods, broadband Internet, smartphones, and laptops.
But wait, that episode that came out fifteen years ago was set only a year or two ago in the series' storyline. How is it that the characters were touting tape decks as the next big thing, but only a short time later, older members of the cast are reminiscing on their old Walkmans, and younger members have no idea what a cassette even is, even though they were the ones lugging them around back in the first few seasons?
It's simple. As the show is set in the "present" day, contemporary technology quickly becomes dated as Tech Marches On, and the writers quietly bring in gadgets appropriate to the year and hope viewers don't notice. This normally works fine until you start watching reruns and notice how dated everything is. The trope only counts in which the characters of the series don't obviously age, and/or it is shown the series is set around the same timeframe throughout. Drawn media such as comic books and animation are the primary culprits, since live-action shows normally let time progress as it does in the real world (ie, events from four seasons ago being stated as four years ago in-universe).
Ah! My Goddess (the manga version). The TV series hangs a lampshade on this when Belldandy comments on Keiichi still keeping his old appliances from the '80s in mint condition.
Detective Conan has a particularly hard time of this, due to suffering from an extreme case of Comic Book Time. The series has ran since 1994 for about two decades, but Word of God claims that only a few months passed in the story. (There's a lot of trouble with that statement, including the number of holidays we've seen, and the changing of the seasons.) Either way, the widespread use of cellphones and personal computers became adapted into the stories concurrently, which created some interesting problems. An early episode had a lunchbox-sized portable fax-machine qualify as an awesome gadget, while a more recent episode had a writer's lack of familiarity with cellphones used as proof that he hadn't left his attic in years. And canonically, those two incidents were - at most - 3 months apart.
This does occur to Kochikame. There are plenty of sci-fi tech in the series, but it does update consumer tech from home computers to cell phones.
Wandering Son began in the early years of The Noughties, which was a fast paced decade for technology, thus this is inevitable for a Slice of Life. For example, early on few characters had cellphones but recently most characters do. There's also a case of Technology Marches On where in the manga, in a volume that came out in 2006, two characters record their voice using a tape recorder. Cut to the 2011 anime adaptation and the scene is changed to them using their cellphones instead. The series barely takes place within 6 years so far, so it seems a bit realistic compared to other examples.
People in the Pokémon world have surprisingly begun to implement current technology in the recent series, despite the series starting in the '90's and not even a year passing since the series began.note Well, maybe? The anime is fairly inconsistent on if time is actually passing or not. This includes giving James an iPad with the new Rocket logo on the back, and characters using Smartphones.
Hi and Lois: Look at the photo on The Other Wikihere, and compare the TV to the modern TV the family has now, not to mention the other conveniences that they have.
Clark Kent's job at the Daily Planet deserves special attention. Originally, he worked there so he'd be aware of disasters happening as soon as possible; as Superman's powers increased and he gained super-hearing and super-vision, that didn't hold water any more, so now he worked there because he thought he could do good influencing public opinion as Clark Kent, and it was a job where nobody would question him always being close to dangerous events and frequently disappearing when something big happened. Meanwhile, the Daily Planet itself changed with the times, always reflecting whatever a modern newspaper would be like — most notably, the Planet's online presence has gone from nonexistent to being their primary focus. Finally, the changing role of newspapers themselves as news delivery systems has led Clark to quit his job twice; once to become a TV anchorman and once to become an independent news blogger.
Blondie's family has been around for decades, and (as noted on the main page) has stayed the same age since the 1940's. However, the family now owns a flat-panel LCD screen and keyboard, presumably attached to a computer of some sort.
And a bit of changing values, too: Whereas Blondie was a simple housewife early in the comic, in the '90s she finally got her own job, running a business no less (as a caterer).
Archie Comics. The characters don't age, but the technology is always up-to-date. It's not something that's just quietly slipped in either; a strip in the late 80s saw Veronica replacing her record collection with CD's, and in a more recent one Archie's parents reminisced about the days of dial-up.
Batman: At the start of his career, a radio small enough to fit in his belt buckle that could be used to send Morse code was bleeding edge. Nowadays he has his own satellite network. Modern stories set in Batman's past tend to fuzz technological details by avoiding showing specific tech. Fortunately a punch to the face has always been a punch to the face.
The Marvel Universe is actually more prone to this than DC, which reboots its continuity every so often, particularly with those characters - Peter Parker, Tony Stark, Reed Richards - who work with fantastic technology, the earliest issues of which involve technology which often wasn't so fantastic 10 years ago or so, when the Fantastic Four took their ill-fated space flight to the Moon (to beat the Russians), and contemporary Marvel continuity began. A prime example? Reading the original Iron Man appearance, one might be amused to discover that the secret to his suit's power was "highly miniaturized transistors."
Cerebro, the mutant-detecting computer from X-Men, first appeared in the 60's using punch-cards and tape drives. It has wildly fluctuated in both appearance and capabilities throughout the years before settling on the ball-shaped room made popular in the movies.
Dick Tracy justifies it with industrial magnate Diet Smith supplying Tracy's tech with continual upgrades.
Film - Live-Action
Very subtly done in The Bourne Series. In The Bourne Identity (2002), all the mobile phones are late-90s basic phones and we see PCs with massive CRT monitors. By The Bourne Supremacy (2004), we start seeing early smartphones and PDAs, such as the HP iPaq used to ID Bourne's (faked) fingerprint, and flatscreen monitors.
In the early Cat Who... books Qwill has a clunky manual typewriter that he refuses to replace with an electric one. In the later ones he has a clunky electric typewriter that he refuses to replace with a word processor. It's still claimed to be the machine he used his entire journalistic career.
Young Wizards: A computer obtained by one of the characters in the third book starts out as a typical 80s Macintosh-like device. By the seventh book, it has "evolved" into a modern-day laptop, despite less than five years passing in-universe.
The gadgets in Alex Rider used to be disguised as Game Boys and early Harry Potter books. He's since moved on to iPods, without aging more than a year.
The fairies in the Artemis Fowl universe are supposed to be high-tech, with technology significantly beyond anything humans have produced. And while some of their tech has remained in Sufficiently Advanced Technology territory, a lot of their technology has quietly become upgraded over the course of the series as real-life human technology has reached new heights, making some of the fairy tech seem backwards in comparison. While the series has progressed forward in time, it's worth noting that in-series, fairy tech has been high-caliber for a long time and is not generally noted as making significant improvements.
Alan Dean Foster started the Humanx Commonwealth series in 1972; its older novels show Flinx looking up information on microfiche, whereas recent ones have him hacking a global computer network when he's only a few years older. Notable in that one of the novels, Bloodhype, was set chronologically near the end of the series, but written back in the 70s. Foster himself acknowledges that this makes for a jarring plunge in tech-level whenever you read them according to the in-universe timeline.
The Helmsman Saga has been started in the 80-s. In the fifth book, Wilf was stated to have a pager. In book 7, he had a mobile phone. In book eight (written in 2011, after a fifteen years' hiatus), he sends SMS messages.
The novel serialization of the Robotech saga. By the last book (#21), cell phones, internet and email were common enough parlance in the real world that references to them were included, despite never being mentioned anywhere in the previous books.
Stargate Atlantis, where (set in the present day) the expedition had a seemingly limitless supply of gadgets, which mysteriously kept updating with rather recognizable new models which hadn't even shipped yet at the show's premiere, in spite of being cut off from Earth until the Dćdalus showed up in Series 2.
This Sci-fi Sitcom long-runner features this in the set design, having had its original heyday during the late-'80s/early-'90s but been revived most recently in 2012. The early seasons feature Holly (the ship's computer, seen as a face on a screen) moving about on R/C tube TV rigs, and Total Immersion Video Games being triangular-shaped VHS tapes, but this has (eventually) evolved over time so that by Season X (the latest season as of this writing) the Red Dwarf comes equipped with flat-screen monitors. Whilst both of these types of technology are present on the same ship, the "just go with it" nature of the show means that it isn't too distracting.
The show hung a massive lampshade on this trope in the 2009 'comeback' miniseries 'Back To Earth', when the characters encounter DVDs and ask "what are these?" since video cassettes were seen in the earlier series to apparently still be ubiquitous in the future. The dialogue reveals that in their timeline at least DVDs swiftly fell out of favour again, owing to humanity's congenital inability to put the discs back in their case: they were re-replaced by VHS tapes as "videos are just too big to lose".
Over the course of the Nancy Drew adventure games, Nancy transitions from using land lines to basic cell phones to camera phones to smartphones, and from borrowing suspects' desktops to owning a laptop to downloading through her phone. In The Secret of the Old Clock, set in the 1920s, the game pokes fun at this by having Nancy's friend Bess having the latest tech— a party line.note A party line was where 2, of often more, households were connected to the same telephone connection.
The entire Street Fighter series takes place across the course of only a few years. Street Fighter IV takes place immediately after Street Fighter II. The story is still taking place in the 1990s, but that isn't stopping C. Viper, Chun-Li, Juri, and a few other characters from using modern smart phones and ultra-thin laptops.
This is somewhat noticeable in the Modern Warfare trilogy, even though the first in the series came out in 2007 and the last one only four years later, as the games try to maintain the feel of bleeding-edge tech. The player character takes out a briefcase computer to guide Predator missiles and helicopter gunnery in 2; these are upgraded to touchscreen tablets in 3, even though it's the exact same conflict set only days apart.
In El Goonish Shive, the teenage main cast has gone from landline phone extensions in bedrooms to flip phones to smartphones.
Other than an early oopsie of many of the students listing modern movies as their favorites in a gender studies class (Willis laments in a decade that'll seem weird that so many 18 year olds would be into classic movies), the pop culture references tend to try to stay as generic as possible (The Nintendo DS/3DS may be replaced, but playing a version of Mario Kart on a handheld device will probably be A Thing for the foreseeable future, for instance. Amber's MMORPG is most likely World of Warcraft but never named directly, and Transformers references are kept as generic as possible, IE "Optimus Prime" and "Bumblebee" being safe choices for future generations).
Sluggy Freelance. The very first strip opened with Torg talking about the potential of the internet in 1997. The march of tech is sometimes downplayed and sometimes lampshaded, especially in the 10th and 15th anniversary strips which redo the first strip but with Torg talking about the internet's potential in 2007 and 2012 instead.
Arthur: Early episodes had Muffy, the rich girl, the only one with a cell phone, and Arthur's family owned a computer that seemed to be command prompt and had a very primitive GUI. Later episodes had everyone else owning a phone, the computers up-to-date with 21st century technology.
The Simpsons: The technology in the early episodes definitely reflected that the show took place around the same time they were produced, the 90s. Bart used a typewriter to write a paper in an early episode, and the kids in the series played video games on what appeared to be a SNES/NES mashup. Later episodes reflected the 2000s/2010s period, though it took until the show's 2009 HD conversion for the family to have a flatscreen rather than the dials-and-rabbit-ears cabinet TV they had. It gets even more bizarre in an episode where Homer remembers his teenage times which happened in "That '90s Show", Homer mentions Sonic the Hedgehog as his idol. The show started 2 years before the first Sonic the Hedgehog game so the game should be a novelty even for Bart.
One episode had a wealthy school that had its own website, which the public schools did not. One of the writers mentioned that it was one of the most dated jokes they had ever done.
Likewise, post-uncancellation, Futurama has been 'updated' with the latest Eye-Phone and most recent scientific gadgets and theories about Time Travel and Evolution, which didn't exist in 1999 back then in Real Life.
In one episode, Amy's phone was shown to be absolutely tiny. When she swore out loud at a "prank" call (actually Kif working up the nerve to talk to her), Leela wondered if she swallowed her phone again. When the episode was aired in the early 2000's, the trend in real life was to make cell phones as small as possible and this was the logical progression. Around the mid 2010's however, the focus shifted towards larger touchscreens, meaning larger phones.
South Park: In early seasons a DVD-player was a sign of rich status, that only one family in town could afford. Now, various characters can be seen buying DVDs, playing Xbox, and having a Facebook account. Yet the boys have only advanced one year in the school.
The episode "The New Terrence and Phillip Movie Trailer" involves the boys watching TV to catch a movie trailer during commercial breaks. It aired in 2002. If it aired after 2005, they could just watch the trailer on Youtube or recorded it on a DVR and skipped to the commercials.
The greater DCAU has something like this, since the original Batman: The Animated Series was deliberately made to evoke the character's 1930's noir roots, while Superman: The Animated Series and others are more modern. As a result, Gotham City got a massive tech upgrade between seasons as BTAS was updated to match STAS.
This has always been inconsistent. BTAS seemed to have modern tech from the start, just with a 30's art-deco aesthetic.
Family Guy is a pretty jarring comparison between the first season in 1999 and its current seasons, though numerous episodes address this issue by introducing new technologies to the family (mostly because they were still new technologies in real life, and ripe for parody.) The series starts off by mentioning using a VCR to tape Monday Night Football, singing about how owning a cellphone was status of great wealth and importance, having a home computer and the internet was completely unheard of. Now, taking advantage of modern technology for the sake of jokes, everyone has a smart phone, the old tube TV was replaced by a Hi-Def LCD, the VCR was replaced by a blu-ray player and Tivo, Stewie makes jokes about Twitter, Lois has a Facebook account, etc etc.
In the 2011 Beavis And Butthead Revival, the technology is more or less up to date with the 2010s. Computers look modern, they mention the internet and modern video games, one episode features a drone, and their TV has a converter box near to the rabbit ears.