Posterous is a new service through which users can post just anything by sending email, its a kind of twitter like microblogging, but unlike microblog here one can put any content using smart auto embedding services of Posterous. The service lets post content from email and content could be audio, video, image, pdf, doc or mp3 and you would get 1GB of space for all this.
One can use any email service such as GMail, Windows Live (Hotmail), Yahoo or any other to do blogging via email and for that you just have to send an email to post @ posterous.com unlike to other blogging services with WYSIWYG editors or so.
The interesting and USP part in this is Posterous intelligently embed the files in different user interfaces like when you post a YouTube video link via email, it automatically embed the video player as such and when you post any audio files it will put a nice Posterous interface for that (see image below) and audio player when you post an mp3 file.
Apart from this, when you send URLs, it will automatically create a link and when an image is send as an attachment it resize it to web friendly size, ...