Torill observes that some Tinderbox webloggers write in spurts, as when Adrian Miles "suddenly pours three weeks of writing into his weblog". As she notes, it's not clear whether or not the difference is a good thing; at this point, all we know is that it's a difference.
One reason for the difference is that, with Tinderbox, you have the option; you can write a note and think about it. With Blogger or Moveable Type, you either write somewhere else or you post immediately.
BloggerPro lets you write a post for future release, as several correspondents point out.
Another reason, of course, might be that people put off FTPing because it's inconvenient or slow or because they forget. That's a technical problem; perhaps we should find a better FTP client, or perhaps we should build this into Tinderbox.
Most of the time, I try to keep a note or two ready in my "unpublished" container, all set for days when there's nothing to write. Having a buffer of finished notes, and another buffer of topics you intend to write about someday, is important to keeping the rhythmn of a site like this.