I started up another blog because I wanted to a placeholder to put all of my thoughts and ideas concerning Web2.0 and Library2.0 resources. (That, and I really wanted to get this cool domain name...)
Even though I have some other blogs, such as this one for putting in family stuff, and this one for science and engineering resources. I have also created blogs for an LIS class and I collaborate with groups of people on various blogs, such as PAM of SLA and for this new journal, Collaborative Librarianship.
I really hope I don't create the same HUGE number of blogs as this guy (he is at 19 and counting...), so I will stop at this one for now.