In a nutshell, this toolbar lets you:
1) Show RSS feed headlines directly in the toolbar with a slick fade-in effect. You can also select from a list of topics (i.e. Technology, Video Gaming, Star Wars) to get headlines from feeds relating to the chosen topic.
2) Be notified when there are updates to RSS feeds you wish to monitor.
3) Share links with friends/family/the world.
There are many other features, such as the ability to create your own topic-based "channel" (with RSS) from a mashup of related RSS feeds. So, for example, you could create an "IT Podcasts" channel which would display all the latest (and most popular) IT podcasts from around the web.
The rest is left for you to discover.