Feedstitch combines multiple RSS feeds into one.

Checking multiple sites for updated information is a hassle. FeedStitch combines not just multiple RSS feeds, but data feeds from popular social networking services to make keeping an eye on things easy. After signing up for a free account (or using your Twitter, Google, AOL, Yahoo, Facebook, or open ID login) you can start entering in RSS feeds and the usernames of Twitter, Flickr, Delicious, GitHub, and Tumblr you want to keep an eye on. You can then group various feeds and usernames into subsets, creating a new RSS feed or JSON file to track just the items you have specified. FeedStitch [via MakeUseOf]