dlvr.it is a website that can take your RSS feed and post new items to Facebook, Twitter, Pinterest, LinkedIn and Google+. You can log in with your Facebook or Twitter accounts, or set up a new account. They're a paid service with no initial free term.
The cost is about $10 per month. For that you can gather up to 50 RSS feeds and post them on up to 10 social media sites. It doesn't only gather links from RSS. There's a browser extension you can install and send links directly to dlvr.it into a que to be shared later.