“Earlier today we reported that Posterous, a popular minimalist blogging service, had added the ability for its users to import their Tumblr content. Tumblr is a competing ‘light blogging’ service - the market leader in fact. Other similar services include Soup.io, Noovo, Vox, Profilactic and even Wordpress.com and Blogger.com are used for this purpose (although they’re more used for long-form blogging).”
There are a lot of posterous users/votes right now, maybe tumblrs haven’t seen it yet?