The BIONICLE web serials were affected by this heavily. When they first began in '07, each week regularly had one or two chapters to offer. At around '10, the chapters were separated by months. After the toy-line ended, LEGO still allowed writer Greg Farshtey to continue doing the serials to tie up loose ends, but they stopped being updated during the summer of '11, and the website where they have been published is now deleted. And the story was nowhere near tidied up at that point. He has since claimed he has no plans to continue writing the serials, since he's too busy and has no place to publish them.
Avatar: The Abridged Series has come to a grinding halt, four episodes short of completing the first season. The last episode was sometime in 2009. The author GanXingba put out a small clip of a scene from the second season, and hinted at possibly doings shorts like that instead of full episodes. That is a bit of a letdown.
After Barbie: Life in the Dreamhouse began its sixth season, Mattel told viewers to expect a new episode every other week. However, sometimes more than two weeks pass without anything new.
The Best Page In The Universe! Initially, Maddox would update his site on a weekly to monthly basis. Now, it's almost a running joke, with updates coming biannually at best. As of January 2010, there has only been one update for the whole year of 2009. Maddox himself is well aware of this, often teasing his readers with comments like, "Now that my book has been published, I can get back to regularly not updating my site".
Team Four Star's Dragonball Z The Abridged Series normally has no set schedule but has flirted with this trope in the past. The team announced that episodes 7 through 9 would all be uploaded before the end of 2008, but only episode 7 was released during the last week of the year, with episode 8 coming a month later and episode 9 a month after that. Later, it was announced that episode 10 would be split into separate videos to be uploaded over the course of a week. Episode 10 Part 2 (of 3) was uploaded about two weeks after Part 1, and the prior announcement made by Team Four Star was "mysteriously" deleted in the interim. Since then, the team has made no promises regarding release dates, presumably having learned their lesson from these instances.
Lampshaded in an episode of the second season where Krillin mentions how, despite having been on Namek for only six days, it has felt like it has taken them a whole year to get that far.
Eric Conveys an Emotion's last update was on April 1st, 2008. But the last time he updated with an emotion was August 10th, 2004.
Gaia Online's Evolving Items are notorious for this. Since the site never officially releases a schedule or declares when the next evolution of any given item will occur, they're free to ignore complaints about the lack of updates. This causes TONS of Internet Backdraft when users (who pay real, actual money for the items in question) express their outrage on the site. The most egregious of these are probably "The Case of Pietro", jokingly named "The Cold Case of Pietro" by its own creator due to lack of updates, and the Kottan Bell, which saw a 75% drop in its marketplace value because of the several months-long wait between evolutions, stuck on phases with dull items. The Catastrophe! item has evolved twice, with the latest evolution having happened in September of '09.
Justified in the last case, in that Catastrophe is a $0.99 EI that is specifically billed as a side-project with occasional unannounced updates (there have been four 'evolutions' thus far, only one advertised) and, unlike most EIs, has no Generations. The update schedule for most items is "once the art is finished." The update schedule for Catastrophe is "when I feel like it/when I've got absolutely nothing else to do except eat and sleep."
It's been suggested, though ultimately disproven, that this trope was the reason for Rapid EIs (basically the same as regular EIs, but with less poses and evolving twice a week for a few weeks) being created. In truth, it was more due to profitability.
Happy Tree Friends has also taken this to ridiculous extremes. The third "season" started in 2007 and has only had 15 episodes, with three in 2010. Since then, very few actual "episodes" have been made; most are just short one-offs.
Originally, the Homestar Runner website was updated with new material twice a week. However, the creators gradually dropped back to every Monday, then to once a week as their schedule dictated, to "if we're putting up anything new we'll let you know three days in advance". This eventually led to an unannounced hiatus of several months in late spring/early summer 2006 (possibly new baby related, like a similar break in 2007), after which they went back on a mostly-weekly schedule.
As of April 12 2010, they haven't properly updated since November. They didn't even do a Decemberween toonnote Decemberween is the Homestar Runner equivalent of Christmas, but they did add and subsequently remove more links to their store, and celebrated Trogday (Trogdor's anniversary) and April Fools' with a parody intro and a new main page based on it. They only returned for an April Fools' Day 2013 short.
They did announce in December that one of The Brothers had a new baby (explaining the lack of Decemberween toon). Presumably the ongoing hiatus is similarly related to their growing family concerns.
Lampshaded when they finally did return for April Fools' Day 2014, where the main homepage is in disrepair.
Chris Bores, aka The Irate Gamer, took this to ridiculous extremes, in part due to his Attention Deficit Creator Disorder. In 2009, he only released two retro reviews, three videos on "video game history", and five "Neo" reviews. In 2010, he's released even fewer.
In 2011, things are slightly looking up. Though attention seems to have shifted away from his video game content towards a series covering the 80s. Confusing since he's boasted about an "epic storyline" for his retro reviews yet he only put out three videos involving it.
Merlin's Revenge: The first game was released around 2000, and the sequel a couple of years later. The members were told that the release date for Merlin's Revenge 3 would be Christmas 2005. This got pushed back a couple of years, to the point of fanbase revolt. In 2007, the developer took an indefinite break from the series, and we still don't have the fourth game. Even though in 2006 there were strictly weekly updates, they too vanished in mid-2007.
Super Mario Bros. Z. The creator initially made a new episode every 2 1/2 months or so. Then he wound up taking a year and a half to release Episode 7. It took another year or so for Episode 8 to come out. then the series was cancelled for good, due to the creator wanting to move on and do other things. Part of this is because the quality and length of the episodes both increased drastically since the beginning. When the creator is packing in roughly six times the material per episode and spending time doing custom sprites, artwork, 3-D models, etc., it's going to take more time. And there was that incident where a troll harassed him to the point where he temporarily canceled the series. The troll went on to brag about it... to his dismay.
MarzGurl can be erratic with her output. Though she has escaped this and is putting out weekly content.
The Nostalgia Chick for a while didn't put much out because she was filming and editing her graduate thesis.
The Nostalgia Critic himself used to have increasingly erratic updates due to his computer. After the first donation drive, he got a new one and had no problems until December 2011, when he had a computer virus.
The most notorious example is That Chick with the Goggles, who has put out only two videos since January 2009 (and only five videos before then, since joining in September 2008). Some of it was justified by computer problems, but she eventually left the site in 2011.
Spoony started suffering some slippage late in 2010, affecting his regular output as well as Wrestle! Wrestle!. After a while he revealed that it was because he was seeking treatment for a rather nasty heart condition, and viewers were willing to forgive. Well, most viewers, anyway.
It was even worse in during much of 2011, when several promised reviews he was going to put up were delayed by months at a time. In November of that same year, he revealed he was suffering from severe depression and other personal problems. He did get back up on his feet later on, but the combination of the severe lack of content and drama between Spoony and the other contributors of TGWTG during that time has cost him some fans.
Linkara'sHistory of Power Rangers has also gone through this. Lewis has emphasized that the series has no set schedule, and due to the other projects he's had lined up along with his main show as well as the work it takes to produce a HOPR episode (watching the series, taking notes, collecting clips and doing the voiceover), it can take months to get them out. All Lewis has to say about the schedule slip is "It's done when it's done."
Bad Movie Beatdown became increasingly infrequent around 2012, as Mathew Buck has apparently taken to doing more episodes of his other show, Projector.
There she is!! step 2 took 2 years to come out, then step 3 took 3 years, where it ended as the next step only took a few months to come out, and the last step was even shorter as it only took 2 months to come out.
Vote Up A Campaign Setting once promised to be released in "Spring 2009." Over a year later... it may not be Vaporware yet, but that's probably due to fan dedication to the discussion threads.
Yu-Gi-Oh! The Abridged Series has slowly reduced in updates. When the third season started, several episodes were supposed to be released over a month's period, only for the season's first episode to be followed by a two-month break. LittleKuriboh has started taking shots at himself for his slow update speed.
StarFox008's Let's Play of Super Mario World Chaos CompleXX ended up lying dormant for five months between the semi-final and final episodes, but that was because he was gathering the requisite beverage ingredients.
The Yogscast and Total Biscuit had promised to release a pair of episodes of their Magicka co-op Let's Play on YouTube each Friday and Saturday, or Saturday and Sunday if they were slightly delayed; the three had increasingly busy schedules starting after Part 8, and they slowed down release to the point that some weeks had no episodes or only a single episode. Total Biscuit explained that he had to do the editing and that Part 14 had severe audio issues, which still weren't fixed when the episode was released two months after recording.
True Capitalist tends to stop broadcasting for a few days after especially trollish episodes, usually as a sort of prolonged Rage Quit, although sometimes it's for other reasons.
Tends to happen in Chaos Fighters as the creator would stop working on main series installments during August and November because of working on Web Series Writing Month and National Novel Writing Month entries. In addition, the main series suffered from this trope twice. First is from August 2010 to July 2011 and the second is December 2011 until February 2012.
ProtonJon of his Let's Play fame is known to fall into this trope very frequently. In fact, he never has a set schedule and has, on several occasions, gone without uploading new content for months or even a year. This is due to Proton Jon's hectic life outside of recording gameplay footage such as school and work. He even took a few jabs at himself for this by saying "see you in 3 months!" in some of his videos and then deciding the joke was bad and moves on.
Particularly bad with his LP of Superman 64. He's now down to uploading one level per year. Though it's a much more involved project than most Lets Plays, involving intensive research into the game and the entire Superman mythos, plus hunting for the game's incredibly numerous glitches.
On April 8, 2013, Chris "Rowdy C" Moore of TV Trash he announced that he would limit himself to either a TV Trash review or a one-off per week, instead of a TV Trash episode and a one-off. But after "Five Other Frak-Ups" on May 20, he went two weeks in a row without any new content.
Given how many sporkers there are for Das Sporking, this tends to happen thanks to work, school, computer problems, lack of interest, and so forth. Some sporkers are better about keeping to a schedule than others, with the most notable ones being Das Mervin (who regularly updates her Breaking Dawn recaps on Fridays) and Gehayi and Ket Makura (who update their Fifty Shades of Grey sporkings on "Catsuit Tuesdays". Some missed deadlines do happen in those instances, but tend to be because of serious illness or personal issues.
Tooncrap, a blog dedicated to reviewing bad cartoons, had two major gaps: one between April 2011 and September 2012, and another between January and June 2013. It was assumed into Game Show Garbage in 2014.
Famicom Dojo season 2 was supposed to be released in 2009 but was instead pushed back to 2010. And then the season premiere was supposed to come out in February, but instead came out in May. And now new episodes are released between long gaps.
WoodenToaster is infamous for this when it comes to releasing new songs.