Ever since the early days of Lotus Notes - I have loved the ability to file information away under categories - sometimes called themes or topics. Many websites are categorized or themed and it makes more efficient browsing.
Almost every page on this website is categorized in over 80 categories. Most blog software supports categorization too though I have yet to fully apply it to own k-log.
Take a look at liveTopics for some interesting technology.
I think categorized blogs will be pretty much standard soon and fgreatly enhance the blogging experience.
