Tagging
I'm going to start using tags to add categories to my posts. It's getting to be a pain to make all the right categories and try to organize my posts. So now with tags I can just make up words to classify each post and then you can use the tags to find posts that interest you. It's kinda like the categories but now I can be more specific and make up categories on the spot. Flickr, del.icio.us, and Technorati use tags, so I'll give them a try too.