A few weeks ago, we talked about Tumblr's most worthy rival, a blogging platform called Posterous. It's just become that much more worthy.

The Y-Combinator startup believes that you should be able to post everything to your blog using email--whether you're uploading pictures, video, audio or just text. A noble gesture it was, but with one fatal flaw: Posterous blogs had no themes. That's right: they were blank white.

This isn't all bad, because Posterous lets you "re-blog" to a bevvy of other services, so you can post to your Tumblr account, Twitter, Drupal, Wordpress, Blogger, and more. Your actual Posterous remained a lame blank archive until today, when the company announced on its blog that it was adding pre-set and customizable themes.

Like Tumblr, Posterous will let you easily alter colors, but also gives you the ability to upload your own header. If you're more code-friendly, you can get in a code up a fancy-pants theme all yourself. There are only five themes--Tumblr has dozens--but presumably there are more to come.