This page is no longer relevant, because I now use WordPress. But have a read anyway, it’s interesting.
It can be used as a weblog, or for many other things. It’s free of course, as are most tools used to create this site, and it’s very well supported by the author, Rael Dornfest, and an active support group.
But it’s overriding advantage to me is its size and simplicity. The code is tiny, less than 50K including plugins. Oh yeah, plugins. While many features are built-in, such as RSS-compatible syndication, weblog-style date and time stamping, support for style templates (‘flavors’ – US spelling), many more features are available by adding plugins, which are simply tiny bits of code you drop in the plugin folder.
It’s based around the folder structure itself – a folder holds all your entries/posts/articles. Each entry is a simple text file. Sub-(and sub-sub-)folders divide them into categories (and subcategories). For example, all my arts entries are under arts/, while the theatre entries are under arts/theatre/, and the entries for the 2004 production of Two are under arts/theatre/two2004. Simple and very effective. No PHP or MySQl required! (just Perl CGI support).
[the site doesn’t run on this software any more, so I’ve broken several links]
Look, I’m just paraphrasing the official site, just read this review of Blosxom 2.0. That rhymes.