I have a Facebook account, and I do try to keep it as minimal as possible, because the company’s continuing policy is to erode as much privacy from user accounts as possible. The EFF just published Six Things You Need to Know About Facebook Connections, which is a handy guide to seeing exactly what they’re sharing (everything) and how. Remember, to Facebook, you’re not a user, you’re a product. Your personal information is bought and sold every day, and there is no “privacy”.
At least with a weblog, I can choose to share what I want with the world.