My answer will be much more like a practical issue rather than a technical issue. Posterous really makes my blogging activity easier: updating post, uploading pictures or even commenting can be done just via e-mail. That’s a really magical platform, I must say.
For a blogger like me, having busy to upgrade here and there and experiencing security issues (like I had when using WordPress) is really wasting my time. All I need is writing and writing –no matter where, when and how. And now, I can do that easily, thanks to Posterous.