Flipboard is a news aggregator. Much like feed readers you've probably used in the past. The difference is that Flipboard reads your Twitter and Facebook streams, scans them for content and present it to you in a fantastic UI.
Flipboard is extremely competent and feels great to use, it's well implemented into Twitter and Facebook functionally making it easy to reweet, comment, like and share.
Flipboard is free in the Appstore right now but I'd recommend giving it a look as fast as you can as a lot of media companies are gunning for Flipboard for scraping material not presented in their RISS feeds. Well see how it pans out in the end but this is really how you'll want to use social media in the future.