While preparing this coming Friday's entry in the "Counting the Collection" series, I had occasion to start thinking about certain trends that have arisen in the various Transformers lines over the years. One major trend these days is for the line to essentially "reset" itself every few years. This is in stark contrast to the original run of the Transformers line, which ran for seven years as simply "Transformers" before hitting a hiatus where no Transformers were produced at all. Now, most lines tend to either have a subtitle (Transformers: Armada, Transformers: Robots in Disguise, for example) or have a clear (if not explicitly named on the packaging) theme running just for that line (this year's movie-related products, last year's "Classics" line).
Sometimes, one line is intended to be in direct continuity with a preceding line ("Armada" led to "Energon," which in turn led to "Cybertron"). Other times, the new line is intended to be a "fresh start" ("Armada" was a clean break from all preceding lines. The movie line is a totally new continuity, as well). This a trend followed by other toy lines that have related fiction, notably "Power Rangers," which after maintaining a line of continuity for a few years, now gets a franchise "reset" every couple of years much as "Transformers" does.
Of course, long-time fans may wish to point out that even the seven years of the original line (often called "Generation One" or "G1") had different continuities in various forms of "G1" media, such as the comic and the cartoon, each being distinct "universes" from each other. However, there is still a sense in which each line has an identifiably unified history running through it, distinct from other lines, which is either explicitly maintained or explicitly rejected when a new line comes along (although there are definitely ambiguous exceptions to this. For example, the Japanese version of "Robots in Disguise" was originally its own distinct entity, but now they retroactively consider it "G1." No, I don't understand how they make this work, either. The American "Robots in Disguise" line still stands alone).
It's certainly easier on new authors and designers to not have to be aware of so many years worth of previous continuity. Still, the toy-makers know that long time fans like to have our references to the way things used to be. This is why each new line seems to find a way to use names like "Optimus Prime," "Starscream," "Megatron," and "Prowl." Generally speaking, the folks at Hasbro no longer intend for, say, the Optimus Prime from the movie line to be the same Optimus Prime that kids in the 80's watched on TV. Rather, they homage the original character by reusing the name, probably using some design elements in common with the original toy (windows on his chest, in Prime's case), and maybe going so far as to cast the same voice actor to play the part in the new medium (Peter Cullen, in Prime's case). This can obviously cause considerable confusion. Although most people "in the know" don't think of "Movie" Prime as the same being as "G1 Prime," the more casual fan who remembers Optimus Prime from his or her childhood will understandably hear the voice of Prime in the movie, see those homaged elements, and believe that the Prime in the movie is simply G1 Prime in a new form. This can then lead to questions like "Why does movie Prime act differently than he did back in the old cartoon?" Such a question doesn't even make sense if you go into the movie understanding that the two Primes are different characters entirely, but if you don't know this already, the question not only makes sense, but can become difficult to answer due to the explanations required to make a person understand why the two Primes are distinct entities.
Ralph Waldo Emerson once wrote "A foolish consistency is the hobgoblin of little minds." I don't think he was saying that maintaining continuity, per se, is a bad thing, but rather that slavishly making sure that all the pieces of new fiction "fit" with all the pieces of older work can be a detriment to the writing as a whole. I think that the folks who create the Transformers toyline (and who therefore hold the rights to the fiction that spins out of it) finally came to understand this after a long stretch with the original toyline, and attempting to "maintain" continuity when they came up with "Generation Two" after the hiatus. Transformers sales did not pick up as they had hoped, and so they went in a new direction with "Beast Wars" (Actually, Beast Wars also tried to maintain continuity at first, but this was dropped when the cartoon first came out, with links to previous continuity being added in later). They'd certainly decided that "full reboot" was the best option by the time "Robots in Disguise" and later "Armada" came out. This does make keeping track of all the histories and characters rather confusing, but I think the quality of the stories that have come out a result (at least, the ones in more recent years, such as the movie and the new animated series) has been far better for it.