** It's rather interesting to listen to the first "Audition Show" with Shirley Booth trying out for the role of Miss Brooks. Mr. Conklin is the head of the Board of Education, not the incoming principal (that role belongs to Mr. Darwell). Miss Brooks' landlady Mrs. Davis is younger, and has a teenaged daughter who Walter Denton intends to drive to school (Denton only drives Miss Brooks when his girlfriend breaks the date). Walter Denton is characterized somewhat in the vein of a DumbJock, and has a much different voice. In fact, Denton's character is more akin to the later Stretch Snodgrass than the Denton who would be a mainstay of the program from Day 1.
** An eyebrow-raising moments in early radio episodes is Walter Denton's contention that he's a great English student. Later, despite his SesquipedalianLoquaciousness, it's firmly established Denton is BookDumb.
** The animosity between Mr. Conklin and Miss Brooks vanishes after "First Day" and remains subdued for most of the first season. Similarly, Mr. Conklin's hatred for Walter Denton is similarly absent. It emerges only after Walter's prank in the original radio version of "Cure That Habit". Mr. Conklin's nickname, "Old Marblehead", doesn't make its first appearance until the radio episode "Mr. Conklin's Carelessness Code". In one first season episode, "Easter Outfit", Walter tells Miss Brooks that Mr. Conklin's nickname amongst the students is "Napoleon".
* ''Radio/AmericanTop40'': The first two years or so of ''[=AT40=]'' show clear evidence of a work in progress. Casey Kasem's delivery was much different during those first couple of years than what fans were accustomed to (beginning around 1973), and even his hosting style was noticeably different. There were relatively fewer stretch stories, with only brief facts about the artists to introduce the songs. Extras – usually oldies or album cuts from the No. 1 album of the week – filled out the show more often. Also, those early shows were in mono only; even FM stations of the time didn't have a stereo option. By late 1972, the show had just about taken the form fans would come to know and tune into for years to come.
** Also, early episodes of [=AT40=] had Casey Kasem attempting to predict what song was going to top the charts the proceeding week, after that week's number one single had finished airing. That was eventually phased out when it was no longer deemed a worthwhile part of the show. (By the way, you can still hear a lot of those earlier editions of [=AT40=] on Sirius XM's '70s on 7 channel, as well as the "Classic ''American Top 40''" channel on the [=iHeartRADIO=] app.)
** Fans who know the show from its late-1970s and 1980s incarnations might be surprised to learn that the Long Distance Dedications, one of the most defining features of the original program, didn't even appear until eight years after the show's debut.
* ''Radio/AmericanCountryCountdown'': In addition to a different host altogether – Lubbock, Texas-based Don Bowman helmed the show – much like its sister program ''[=AT40=]'', there were more extras and "sneak peek" songs played. In addition, during the earliest programs Bowman liberally made use of his humor in between songs, and many of his jokes today would be clearly considered politically incorrect today (e.g., on the third episode from October 1973, he quipped, "How do you get a horse to stop complaining about the cold in winter? Shoot him in the summertime!"); Bowman eventually scaled back on these jokes when complaint letters -- calling the jokes mean-spirited -- started coming again, and once Bob Kingsley came aboard as producer this could have had an impact, too. During the first year or so, outro bumpers (mixed in with the trademark "My Kind of Country, My Kind of Music" outros) sometimes used an alternate format with different lyrics and a top country artist of the day, including Bobby Bare and Music/TomTHall.
** Bob Kingsley took over in 1978, and his tenure had its oddities. Most notably, after the show expanded to four hours in TheEighties, the endcaps to the first through third hours (after songs #31, #21, and #11 respectively) were previous #1 hits, presented in either chronological or alphabetical order. Also, the "ACC Calendar" feature spotlighting a story on an older song, could occur anywhere in the show. By 1996, "ACC Calendar" was moved to the end of the third hour (after the #11 song), and the endcaps to the first and second hours became dedicated to listener requests, where Bob would read a listener's story pertaining to a certain song, and then play that song for them.
** After Bob left, he was replaced by Kix Brooks of Music/BrooksAndDunn. The earliest Kix programs from 2006 and 2007 often had him breaking away from the countdown to play songs he wrote for other artists, or Brooks & Dunn songs he sang lead on (including "You're Gonna Miss Me When I'm Gone," the only No. 1 [=B&D=] hit featuring Brooks on lead vocals). Over time, the "extra" songs came to be recent recurrents (big hits that fell off the charts within the past year or two), followed by a snippet on the artist in question. The show also started out at 40 positions, but was quickly cut to 30 (thus leading to more filler) before reverting to 40.
* Bob founded ''Radio/BobKingsleysCountryTop40'' in 2006 after leaving ACC. His early [=CT40=] shows, though largely identical in format to latter-day ACC, had a couple lesser examples of this trope. Most notably, he originally used a PreviouslyOn segment identical to ACC's, consisting of the previous week's #1 hit, played either in its entirety or an edited-down version. This was quickly replaced by snippets of the previous week's Top 5 hits. It also took a couple years before he introduced "[=CT40=] Flashback", a once-a-month segment just before the #5 song in which Bob presents trivia on a certain year in history, then plays snippets from the Top 5 songs on the corresponding month in that year. By 2013, he also swapped out one of the two listener requests for "[=CT40=] Vault", a feature where he would play snippets of previous #1 hits from prior years, then the entirety of a more recent #1 hit.
* For the first few months of the radio game show ''Radio/AskMeAnother'', hostess Ophira Eisenberg would drop hints about the identity of the guest throughout the show instead of announcing it at the opening.
* ''TheBrewingNetwork'': Listen to the first few episodes of The Jamil Show and you'll hear a very reserved, quiet Jamil hosting. This was brought up in Lunch Meet, as Justin tries to imitate Jamil's quiet, softly spoken demeanor. Fast forward to the time they wrap up the BJCP, Jamil is much more extroverted, using sexual innuendo all the time (which is encouraged when the network gets sponsorship from Adam and Eve) and being more natural as he got used to being on the radio.
* The earlier episodes of Radio/StusShow (from 2006 and some of 2007) had a more laid-back feel. Stu was more calm and collected, interviews were more straight-laced (but still had humorous moments here and there), phone calls from listeners was more regular, and Stu often had trivia contests for listeners (usually just before commercial breaks). The contests have since been relegated to the New Year's Eve or Christmas specials, as contests tended to detract from the interviews.
* When Radio/TrueCapitalist began, Ghost was a fairly ordinary (if rather extreme) conservative talk show host. It wasn't until the more bizarre personalities like the Internet Buttstalker and the Ghetto Capitalist showed up that he fully became the [[LargeHam Large Hambone]] that we know today.
* The early instalments of ''Radio/TheGoonShow'' had four people (the regular three plus Creator/MichaelBentine), and were written as multiple short sketches rather than the extended if incoherent stories featuring a CommediaDellArteTroupe of madmen that became the show's typical structure later in its life. It also took quite a while for Ned Seagoon, Bluebottle and Grytpype-Thynne to show up.
* Radio/TheHowardSternShow had Howard speaking in a much more high pitched voice than his trademark smooth baritone. His head writer Jackie the Jokeman and producer Baba Booey were also not yet on the show, removing the 2 main butts of his jokes, as well as not having his "Wack Pack" of bizarre and disturbed regular callers.
* ''Radio/AdventuresInOdyssey'' had its origins in sort-of-a protoype version of the show called "Family Portraits", which, while still featuring some main characters such as Mr. Whittaker and Tom Riley, was more focused on the families of Odyssey. Positive reception to the "test" series lead to the debut of the main series itself, now re-tooled into "Odyssey U.S.A.". This title remained for several months until the main crew learned about how [[GermansLoveDavidHasselhoff popular the show was in Canada]], thus retitling it to ''Adventures In Odyssey''.
* ''Radio/TheInfiniteMonkeyCage'' started out as a mix of discussion between the presenters and studio guests and some scripted comedy sketches. The sketches were dropped after the first series.