Since posterous is new and I am new to posterous and from what I hear they are planning on rolling out some new features over the summer I'll be adding an ongoing list of featues I would like to see added because I like to believe people care about my opinion.

• Tags, I'm addicted to them, love them.  Please, let's see them.
• Integration with Flickr, PicasaWeb and other photo hosting sites.
• Ability to add photos inline text while creating a new post from the web without having to code it.
• Themes/customizable CSS

That's it so far.  And to be fair I'll also add a few things I like about posterous from my brief experience.

• Fast, clean interface.
• Although the CSS is not currently customizable, the default look of each site is probably one of the best default looks of any blogging platform.
• Fantastic way to display multiple photos when sent attached in an email (although eventually it would be nice to have this feature without having to attach multiple photos to an email.

Keep up the great work.