You might want to sign up if you: a) Want more traffic for your blog, and b) Like looking at other people's blogs.
You register your blog- for free!- and then for every blog that you visit, you earn credits. Then you can use the credits to direct traffic toward your blog. Or if you want you can use your credits to "rent" space on someone else's blog, like
over there in the sidebar. You should check that shit out, it's good! So much funny stuff.
Also, I've been reading some really great blogs over there. For real. I've stumbled upon some real gems I probably wouldn't have found otherwise. I'll be updating my link list as soon as I tear myself away from the Battle of the Blogs. That's a little BlogExplosion feature where I go to get MY ASS KICKED. Like I said, it's free, and you rack up a lot of visitors really quickly. Check it out.