But if your blog is hosted by a third party (say Posterous), having blog.domain.com is very easy to set up, but domain.com/blog isn't? (Is it actually even possible at all?)
This is a total pain in Tumblr. I don't even think it's possible, or at least, haven't figured it out in 3 days of trying. So now I'm weighing whether the community/distribution of Tumblr is worth trading for a little bit of SEO. In our case, a social iPhone app, I think we're keeping Tumblr.
