Keri Arthur discusses what to do put on a Web site:
http://www.keriarthur.com/writerswebsite.html
Most notably what not to put on a Web site, too. I used to do a Web site for an actor--mind you, this was a well-known actor who had several series and was in a couple of big films, but not a mega-star. Personal information was the one thing we kept off the site, and it was the one thing that fans hated about the site. They would have been happy to see us post his underwear size! I've since seen horrifying disclosures of personal information on blogs, like what drugs the person is taking.
Let's see what else:
If you put up a picture of yourself, make sure it's a good picture. I visited a popular children's author's site, and she had this terrible photo of herself. It was in black and white; her hair was long and stringy; she was wearing a cheap t-shirt; and she was scowling at the camera. It was, bluntly, an ugly photo. I think her publisher must have gotten on her because the photo disappeared right before a release and was replaced with a better one.
One of the agents has mentioned the following: Providing "extra scenes"--things that were clipped from the book but that fans may want to see.
Providing a lexicon for a series.
Some of the authors have FAQs or, like Mercedes Lackey, answer questions from fans. I would tend to avoid the second one because of my experience with the actor's site. Fans can ask the dumbest questions, and there are also some agressive fans when it comes to getting information. We had one guy who would ask a question, and we'd post the answer on the site. A few weeks later, we'd get a slightly different variation of the same question from him, looking for, I imagine, a different answer than what he got. A lot of times we'd also get new people in who'd ask the same questions that had been already asked, and we'd just post a link to the question (though, to be fair here, no one realizes their question has been answered hundreds of times by the actor already).
Amy Tan has myths and legends on her site--a page prompted because of misinformation about her that is accepted as fact on the Internet.
http://www.amytan.net/MythsAndLegends.aspx
Douglas Preston/Lincoln Child have a
Rogue's Gallery, which are bad reviews. They also have fan art posted.