When I upgraded this blog to Movable Type 4.0 I wanted more then anything to completely start fresh. To rethink my URL structure, the use of hyphens vs. underscores in my file names and so on and so forth, but there was one thing stopping me, and you will think me egotistical for caring about it: page rank.
Bottom line I was worried about the incoming links that would break if I decided to change anything. But it occurred to me that all the data I needed to create a blog from scratch and keep links fresh and active was right there in front of me: in the database and on the file system.
So I began writing a plugin that would help track broken links on my blog and then, if possible, attempt to fix the problem by redirecting the user to the proper file or resource automatically. I am calling the plugin "Clean Sweep" and am releasing it in beta form today.