I have added a couple of things to the sidebar of my blog (to the right of this text).
The first is a subscription widget. Subscribe to me! I just started using Google Reader which is amazing and I highly recommend it if you read more than 2 blogs (or would like to have the time to do so). It allows you to see updates / new post titles and have the option to read the feed complete with images from all of them almost simultaneously. You can also star things you like and create your own tags to categorize things for easy reference. Sharing things is easier too. Here's a post on ThisYoungHouse with more info and the "getting started" video.
Next, I've posted a Twitter widget featuring my latest Twitter updates. Follow me on Twitter! I haven't been using it much but as we all know after the recent plane crash photos that were first posted by a Twitter user, it's where it's at!
Lastly, I posted a playlist. This feature is possible via ILike.com which is another great social media site but for sharing music recommendations, playlists, concert alerts, etc.