Avoid postings that could enable a stranger to locate you. That includes your last name, the name of your school or sports teams, the town you live in and where you hang out. [...]
Avoid getting together with someone you "meet" through a blog unless you are certain of their actual identity. If you do meet them, arrange the meeting in a public place and bring some friends along.
There are more tips for parents, teachers, kids, etc. so go take a look at BlogSafety.com. And yes, they even have a weblog of their own (powered by Blogger of course!).