A children's sitcom produced for the Disney Channel, which premiered on January 17, 2003 and is still in production as of late 2004, with new episodes airing on Fridays (though not every week) and reruns daily and on ABC Saturday mornings.
The title character is played by Raven-Symone (credited as the single-named Raven), and the character is also named Raven. She played Olivia on The Cosby Show back in the late '80s, and also appeared on Star Search. She's currently working for the Disney organization in several capacities, doing the voice of Monique in the animated Kim Possible show, singing as a recording artist on a Disney-owned record label, and appearing in several Disney movies (e.g., Princess Diaries 2) as well as her starring role in That's So Raven.
The "gimmick" of this show is that Raven has psychic visions, seeing fleeting images of the future. Most of the plots are concerned with the reactions of Raven and her friends to these visions, which usually consist of doing just the wrong thing, making the situation worse than it would have been if they had ignored the vision altogether.
Since this and Lizzie McGuire are the Disney Channel's leading live-action shows, it's hard to resist comparing and contrasting the two. There are a few superficial similarities -- both feature a female lead character who's part of a girl-girl-boy best-friend trio, and who also has an annoying, scheming little brother and parents who embarrass the kids by trying to be "hip". However, there are significant differences in the characters, beyond the obvious ones (Lizzie is white and Raven is black; Raven is slightly older than Lizzie and is in high school rather than middle school).
While Lizzie is portrayed as a basically good, honest, upstanding, trustworthy person -- any time the plotlines call for her to do something sneaky or nasty, it's clearly portrayed as a temporary lapse from which she returns to her senses by the end of the episode -- Raven isn't so nice. She seems inclined to lie, cheat, and steal whenever she thinks she can get away with it. For instance, in one episode, when she attempts to open her stuck locker, some adjacent lockers pop open, and she spots a CD she likes in somebody else's locker; she doesn't think twice before deciding to "borrow" it.
Raven's best-friend group is also more dysfunctional than Lizzie's; rather than using their good sense to pull one another back to earth when they're inclined to go off on a wild, impractical scheme, they're more likely to go along with the plan (no matter how idiotic) and stick with it as it spirals out of control. This can make for fun plotlines, but isn't a very sensible life strategy. Raven and her friends might be more fun to be with than Lizzie and her friends, but I'd feel safer leaving my wallet lying around when Lizzie was visiting than when Raven was here.
Raven doesn't seem all that smart, or to have the ability to learn from her mistakes; for instance, on more than one occasion (and sometimes several times in the same episode), she has reacted to a vision of something unpleasant by saying just the "right" thing to cause it to happen just as she saw it, to her distress; you'd think she'd eventually learn to keep her mouth shut.
The minor characters on Raven are extremely one-dimensional; several of them seem to exist only for a single gag, like the teacher (later turned principal) who spits every time he talks, and the student with strong body odor. This reminds me of Saturday Night Live at the low points of its history, when the writers have run out of new ideas and the skits consist of endless appearances of the same single-joke characters who were mildly humorous the first time they appeared.
Online fan fiction authors seem to find more potential in the Lizzie characters than Raven, too; at FanFiction.net there are 2,478 Lizzie McGuire fan fictions and only one for That's So Raven (though at least one of the Lizzie fanfics is a crossover in which Raven appears). However, That's So Raven is not without its own popularity; it's reportedly an international success, getting high ratings in Europe.
A Raven feature film is reportedly on its way in a couple of years.