I think the pleasure of completed work is what makes blogging so popular. You have to believe most bloggers have few if any actual readers. The writers are in it for other reasons. Blogging is like work, but without coworkers thwarting you at every turn. All you get is the pleasure of a completed task.
Source: The Dilbert Blog: Work Pleasure: http://dilbertblog.typepad.com/the_dilbert_blog/2007/12/work-pleasure.html
Contributed by: ~C4Chaos