I copy Digg's information for you guys. Digg is very popular site for shareing files. each person can upload your papers into site. I have been seen a lot of company trying to do this service.
By the way, When i design the site of IGOABROAD.COM, I also provide sharing files but all about academics. However, only members can read those papers. I always have a question about this kind of serivce. how can they make money? from ads? from people?

How their employees survival without salaries?


What is Digg?
Digg is a place for people to discover and share content from anywhere on the web. From the biggest online destinations to the most obscure blog, Digg surfaces the best stuff as voted on by our users. You won’t find editors at Digg — we’re here to provide a place where people can collectively determine the value of content and we’re changing the way people consume information online.
How do we do this? Everything on Digg — from news to videos to images to Podcasts — is submitted by our community (that would be you). Once something is submitted, other people see it and Digg what they like best. If your submission rocks and receives enough Diggs, it is promoted to the front page for the millions of our visitors to see.
And it doesn’t stop there. Because Digg is all about sharing and discovery, there’s a conversation that happens around the content. We’re here to promote that conversation and provide tools for our community to discuss the topics that they’re passionate about. By looking at information through the lens of the collective community on Digg, you’ll always find something interesting and unique. We’re committed to giving every piece of content on the web an equal shot at being the next big thing.