posterousSachin Agarwal created Posterous as a way for his parents to be able to see what he posted online. Two years later the blog publishing tool has more than 15 million monthly users, but experts still wonder whether its ultra simple functionality can catapult it into the rarefied air of Facebook or Twitter.

“No one has solved the problem of how does my 60-year-old dad see my photos,” said Agarwal, who launched his San Francisco, California-based technology startup two years ago with friend and former Stanford University alum Garry Tan. He said it was important for him that Posterous appealed to people who may be intimidated by the terms “blogging” and “social media.” “We don’t want to be thought of as a tech toy for Silicon Valley geeks. We’re surrounded by a lot of crazy tech, but our goal is to be so much more universal and applicable to normal people.”

Agarwal said Posterous gets around the need for having users register accounts by getting them to post their content – text, photos and video – directly via email to a central Posterous email address, which is then immediately published online in the form of a blog.

“The idea here is that I can post super easily via email from my phone or desktop or whatever while on the go and whatever I post it gets distributed out to the people I care about sharing it with,” said Agarwal, who worked at Apple for six years prior to launching Posterous.

THE PITCH

Last month the startup raised another $4.4 million in venture capital in a Series A round led by Silicon Valley firm Redpoint Ventures, which had previously invested in MySpace, Netflix and TiVo.