I think the Posterous/Tumblr dichotomy is a false one. Where they're both ultra-simple microblogging platforms, tumblr is easily more community centric, insula

I think the Posterous/Tumblr dichotomy is a false one. Where they're both ultra-simple microblogging platforms, tumblr is easily more community centric, insular in focus than Posterous, and in my opinion that's where it's strength is. Nearly every avenue of a default feature now found in tumblr has come from innovation that users have made use of when the site was still young and lacked considerable features.