PubSub offers a number of ways to automatically track subjects of particular interest to you. For some time I have used the RSS-based alert service which tracks a 'stack' of terms I created:
The alerts show up in my RSS news aggregator (I use SAGE) and appear in bold face when there's news.
I've more recently started using PubSub's 'link ranks' tool that tracks your blog every day and measures the number of your posts (entries), outlinks, and inlinks. You're then presented with your blog's rank, based on PubSub's measurement of "the strength, persistence, and vitality of links appearing in over 23 million sources that PubSub monitors."
Here's my link rank. It's quite modest. . .
. . . but it's useful information, and helps inspire me to keep posting. To track your blog's link rank, go to this page and enter your URL.