If you’re a regular blog reader, it’s easy to use your reader as a topic tracker.  You can do any Google News or Google Blog search and subscribe to the results as an RSS feed.  Some readers (such as BlogBridge) have the built-in ability to construct these “smart feeds”.

I use this method to track a long list of interest topics:  news about companies I’ve invested in, competitors, people I work with, etc.  It’s a very efficient way to cover a range of topics.