Canary Beck has a really interesting and provocative and long analysis of the types of Second Life, based on her 8 years of being an SLer, which she categories in four ways: Real-Fake, Real-Real, Fake-Fake, Fake-Real. You should read it all here, but I wanted to highlight a couple of my favorite insights before you go:
The very most popular SL places in terms of traffic are Fake-Fake:
[F]ake-fake sims are not what they say they are, and not true to themselves. Sims like this are harder to find because they tend to not be often photographed, or written about. I believe we tend to model most simulations on either originals we have experienced in the real world or build them in ways that are entirely impossible in the real world. Fake-fake sims, however, seem to be a haphazard mixture of the two.
Self-touted as Second Life’s Premier Dance Venue (to be fair they did win at least one Avi’s Choice award in their category), nearly everyone in Second Life is aware of Frank’s. According to Metaverse Business, Frank’s currently places as Second Life’s 2nd most popular sim – and its most popularGeneral sim. The interesting thing about Frank’s (pictured below), is that it’s neither a “ballroom” (as it says in its description), nor does it really play jazz. What you actually get is a mall leading to a palatial open-air dance floor that bears little resemblance to any jazz music venue I’ve ever seen. It has a formal dress code where men dress in tails and the ladies dress in ball gowns (clothing which isn’t at all associated with most jazz clubs in real life) and instead of jazz, Frank’s mainly streams easy-listening music.
And she gives many other examples in that category. (By the way, she's not saying "Fake-fake" as a value judgement.) She's very astute to note that a popular sim like Frank's Place doesn't, well, feel like an actual place (though clearly, a lot of people love it all the same.) By contrast: