Gwenda Bond pointed out that Caitlin Kiernan has made a valuable attack on the term "self-indulgent" as a critical insult of a piece of writing:
...this is one of those things that strikes me very odd, like reviewers accusing an author of writing in a way that seems "artificial" or "self-conscious." It is, of course, a necessary prerequisite of fiction that one employ the artifice of language and that one exist in an intensely self-conscious state. Same with "self-indulgent." What could possibly be more self-indulgent than the act of writing fantastic fiction? The author is indulging her- or himself in the expression of the fantasy, and, likewise, the readers are indulging themselves in the luxury of someone else's fantasy. I've never written a story that wasn't self-indulgent. Neither has any other fantasy or sf author. We indulge our interests, our obsessions, and assume that someone out there will feel as passionately about X as we do.
I agree that it's an entirely inappropriate term (though I may have perhaps used it myself; I hope not), but how it gets used is, nonetheless, interesting. Let's look at some random and unscientifically selected examples:
  • From a review of an Ani DiFranco CD: subtitle: "Self-Indulgent, Self-Righteous Babe"; from text: "an overly indulgent song which utilizes an answering machine message that has little to do with the actual song save for a single shared line"

  • From a review of the movie The Anniversary Party: "I would have liked to have written the film off as self-indulgent claptrap made by some self-indulgent actors and starring their self-indulgent friends. But, the film, tho' seriously flawed is very human, perceptive and emotional."

  • From a review of the book Headless by Benjamin Weissman: "little more than a series of self-indulgent, self-impressed, self-titillating set pieces of forced weirdness and utter pointlessness."

  • From a review of the Criterion Collection edition of John Cassevetes films: "Many, including Leonard Maltin and Ephraim Katz, have labeled Cassavetes self-indulgent. Demanding and austere, perhaps, but self-indulgent? Not once does he impose directorial flourishes of the kind we expect from Hitchcock, Fellini, or Spielberg. And he gave everything he had--money, script, crew, ideas, time, loyalty, ego, and energy--to his actors and their search for emotional honesty. They returned his graciousness with performances startling in their disregard of flattery."

  • Finally, from a reader's response to Mervyn Peake: "To sum it up in the best possible way, its BORING! stagnated, fossilized, long and very Self indulgent. I just didn't like what Mervyn Peake was telling me. So what happens ( very little if you ask me )..."
There is something people are responding to here, a certain general commonality in the use of the term "self-indulgent". It is the idea that the creator of the work under discussion has done something that does not please the person discussing it, and the person discussing it has decided that the something was not worth doing, and that the creator probably knew this in the beginning. Thus, Ani DiFranco is self-indulgent because everybody knows answering machine messages don't belong in songs; The Anniversary Party would have been self-indulgent if it had not been "human, perceptive and emotional" (note the multiple selves capable of being indulged in that review -- it's a potential orgy of mutual masturbators); Headless is self-indulgent because its weirdness does not titillate, impress, or indulge the reviewer; Cassevetes was not self-indulgent because his films drew no attention to the director himself, and, instead, involved many sacrifices of vanity; and Peake is self-indulgent because the reader "just didn't like what Mervyn Peake was telling" him. Because, like, if it's not about you, then it's self-indulgent.

What reviewers who use the term "self-indulgent" are suggesting is that the person created something they knew the reviewer wouldn't like, but they went ahead, the bastard, and did it anyway.

I should probably note here that I'm not suggesting the reviewers are all maligning masterpieces. A judgment of whether a work is worthwhile or not is less interesting to me than how such a conclusion is reached (call me self-indulgent). It's not the inaccuracy of the term that bothers me so much as the argument it hides: an accusation of self-indulgence, like an accusation of "elitism", lets a reviewer disguise the fact that they're trying to speak for some imaginary mass audience, to say "I did not understand/appreciate/enjoy X, and therefore you should not, either." (Which is essentially what one of the commentors to Kiernan's post suggested: "So, the reviewer is basically saying, 'It doesn't interest me, so it shouldn't interest anyone else,' but taking a roundabout way of saying it so as, perhaps, to stave of consciousness of this indiscretion.") I suppose all of us who make our opinions public are doing this to some extent, trying to shape a consensus to make ourselves feel less alone, but there are many more subtle, nuanced, and useful ways of doing it than throwing around terms like "self-indulgent".

Update: Or maybe this is wrongheaded.