I've made an editorial decision to overrule the 18th Edition of the Bluebook on citing blogs, because I've decided it's just wrong. Blog posts should be cited like regular articles are cited. Therefore it should be this:
Susan Crawford, Onward, SUSAN CRAWFORD BLOG, Apr. 27, 2006, http://scrawford.blogware.com/blog/_archives/2006/4/27/1917067.html.
and not:
Susan Crawford Blog, http://scrawford.blogware.com/blog/ (Apr. 27 2006 22:05 EDT).
Among the flaws of the proscribed format, they seem to be a little too trusting in the accuracy of the date stamps...
The important thing about a cite is that it indicate who said what and when, none of which is captured by the Bluebook form. (In fact, the only reason Susan Crawford name shows up at all is that she used it for her blog title. Poor Howard Bashman, though, who foolishly chose a non-eponymous blog name...)