Microblogger shootout: Posterous Spaces vs. Tumblr - Computerworld
Conclusions
Both Tumblr and Posterous Spaces help new or time-strapped bloggers establish a solid online presence. Their sites can be destinations in themselves or front ends to other social networking sites. But for my money (in the sense that time is money), Posterous Spaces has a usability edge over Tumblr.
Tumblr provides a lot of unusual and handy features, such as posting by phone and instant messenger and tagging multiple posts with a single mass-editing tool. But other basic tasks involve much more clicking around than Posterous Spaces requires: You can't change your profile picture and site description in the same place; you have to register at a different site to enable comments on your blog; and the list goes on.
Posterous Spaces processes all kinds of media, from audio and video files to entire galleries of graphics and even PDFs, and quickly delivers a smart and functional blog, complete with seamlessly embedded viewers. Though both services handle posting by email, Posterous Spaces handles more media types more smoothly and rapidly.
Great in-depth review of Posterous Spaces worth checking out



