Textpattern is a CMS (content management system) and blogging tool. It is elegant, well designed, and no one uses it (well, very few people). I like it, but I have discovered they've updated their logo. Call me old fashioned, but I liked the old one better.
I will admit that the newer logo is bolder, and probably easier to print on T-shirts and the like.. but the old one just resonates with me.