I upgraded WordPress from 2.2 to 2.6. It told me it needed to upgrade the database. OK, sure. So when I get things working again, I noticed that there were many corrupted characters and stuff.
I call upon the WP team to do a bit more testing in the future. Hell maybe I will help with the next upgrade scripts... Yeah, we will see if I ever find the time to donate to projects like WordPress.
Now that I've lost my categories, it is nice to see more effective use of AJAX in the admin user interface. It speeds up the adding of tags to my posts. I like tags better than categories anyway.
More on WordPress 2.6 after I have had time to play with it more. Oh, have I mentioned that I am posting this from the wordpress iPhone App? Outstanding!