San Francisco based Posterous, a fast growing publishing platform, has taken a $4.4 million investment from Redpoint Ventures. Partner Satish Dharmaraj, who is also an individual investor in Posterous, led the round and joins the company’s board of directors (and he maintains his personal blog at Posterous here).

Posterous, founded in 2008 by Sachin Agarwal, Garry Tan and Brett Gibson, is a Y Combinator company that began as a way for users to very easily post pictures online. Its appeal lies in its simplicity – users can just email a photo to post@posterous.com and an account is immediately created for them. But today people are using Posterous for videos and text blogs as well. Users can change the CSS and even use their own domain names – see Guy Kawasaki’s HolKaw blog, for example, which is run by Posterous.