I must admit, as a reader, it's nice to have a Twitter account to follow should I want to read 140-character missives from my literary heroes at 3:00 AM, and I do like the idea of being pretend bros with my favorite authors on Facebook. When I've read a book I really enjoy, however, and I want to read more work by that author or learn more about him/her, I generally throw their name into Google in the hopes of finding an author website.
Websites are more crucial than social networking sites (or even author blogs, although many an author website sports a blog as a component) in that they provide a relatively self-contained, centralized point on the web at which readers can learn about upcoming author readings, other books by the author, reviews, the author's biography, and so on.
A few rules of thumb, in the oft-used and ne'er-gone-wrong Bullet-O-Vision™:
· Give your website a modern feel. No 1996-style frames, animated .gifs, tiled backgrounds of your dog, rainbow page breaks, &c. Hire a professional (or your teenage son) if need be.
· Less is more. You don't need to record every single award you've won or article you've written since middle school; stick to the basics.
· Choose a good domain name. Hint: "http://www.newjohnsmith1-2-3today.info/" is not a good domain name.
· If you've got an agent and/or publisher, make sure they link to your site. Also, if you do decide to rock the Facebook/Twitter frontiers, make sure those accounts link back to your site, as well.
· Use Google Analytics (or a similar service) to track the number of visits, page views, &c your site receives on a daily/weekly/monthly basis. You'll be glad you did.