Amanda Hocking, on her sales: "I guess what I'm saying is that just because I sell a million books self-publishing, it doesn't mean everybody will. In fact, more people will sell less than 100 copies of their books self-publishing than will sell 10,000 books. I don't mean that to be mean, and just because a book doesn't sell well doesn't mean it's a bad book. It's just the nature of the business."
True. There may be a tendency amongst indie authors to overgeneralize: Oh, if Amanda Hocking sold a million books, then I can too! But self-publishing is really no different from any other sort of publishing. Does anyone really go into writing seriously thinking they can sell as many books as J.K. Rowling? Of course not. Most of us just want to sell some books, reach some readers, and (ideally, but not usually) make a living at it. We're usually very aware that we aren't likely to sell a million books (even if we have pleasant daydreams along those lines from time to time).
However, I do think that we also need to acknowledge that quite a few people are making a lot of money at indie publishing, and the number seems to be growing all the time. Self-publishing used to be a lightning-in-a-bottle kind of thing-- if you got out there and peddled your book all over creation, you might manage to sell thousands of copies, and if you were super lucky (like that kid who wrote Eragon), you might get a traditional publishing contract.
Those days are gone. Success at indie publishing is no longer an incredibly rare event. Selling a million books? Sure, that's rare-- but then, it's very rare in traditional publishing, too. But making a living as an indie author, or at least making a decent amount, seems more and more feasible all the time. It's also far more likely for an indie with good sales to get a contract with a traditional publisher... if you want one.
So yes, don't be disappointed when you don't sell a million books. But don't be surprised if you manage to pay some of your bills, either.