I'm yet to find a blogging solution that really scales well. Wordpress is nice, but as you add more plugins to it you end up putting a lot of SQL queries through each and every time you load a page etc., which can cause issues
MT is nice as well and has the added advantage of building static HTML files instead of relying solely on the database backend.
Typo looks like it could prove to be useful, though I've no idea what kind of footprint it has
Text Pattern - seems to be very functional |