Now, mod_blog also recreates some files whenever a new entry is made, but it's not quite as bad as Grey Matter or Moveable Type from what I understand. Three files are created—the first is the main page and that is for speed reasons, as that page is most likely to be loaded. It doesn't have to be made—it could be generated dynamically when requested (in fact, that's how I was doing it originally). The second file is the RSS file, and while it too could be generated dynamically, again for speed reasons I build a pre-cached version if you will. The third file is a recent addition and it's the Mozilla/Netscape Sidebar page and again, like the other two, could be generated dynamically, but for speed reasons …
Now the posting speed is another issue. Having used the Grey Matter interface, yes, that is a bit slow to respond since there is a lot of file building going on. Radio appears to respond faster, but that's because it spawns a background task to do the file rebuilding; it doesn't pause the interface until it's done. mod_blog, on the other hand, is different. The email interface responds quickly, since the email client will batch it up for sending, then the server will batch it up for sending and finally it'll arrive and be processed, so via email, the process seems instantaneous, although it may take a minute or two for everything to be processed.
The web interface is fast—less than a minute and that includes the three files being created, plus sending notification to Weblogs.com and sending the email notification (granted, there are only a few people signed up for that right now, but if it becomes an issue I can spawn a background task to send the email).
This on a 33 MHz 486 (and yes, the software is in C but what processing is done, it might be a tad slower in Perl—not entirely sure).
Archiving—that's a non-issue with mod_blog. The whole site here is dynamic (well, except for three pre-generated pages) and the concept of building archive pages just doesn't apply. Granted, I have control over the server so I can do that, but not everyone has such access. Different tools for different needs.