RSS (Really Simple Syndication) is the underlying technology that enables sharing of blog posts, podcasts, news headlines, and other content on the web. In this lesson you will create Popfly mashups to create a web gadget to display RSS feeds, you will learn to locate RSS feeds that contain information about your activities on popular social and networking web sites and combine them to aggregate a “trail” of your online presence, and you will combine and filter RSS feeds from topics of interest in order to display only those items of interest to you.
Your News, Gadgets, and Online Trails: Mashing RSS Feeds in Popfly (PDF)