I've been using Yahoo! Alerts for a couple of months now, and I'm very happy with the service.
Last November, I wrote about Google Alerts, Social Mention, etc. and they are also nice. However, I am particularly happy with how Yahoo!Alerts is popping up with information for me.
Now, admittedly I am only using one aspect of Yahoo! Alerts: their News Alerts, where I choose keywords and then receive summaries in email of top news stories that correspond to those keywords. For example, I have Yahoo! Alerts set up for "copyright infringement" and "blogging."
However, the service offers a lot of options, and you may find other things more to your liking. Check it out.
Interestingly, once I have notice of the news story or blog post via Yahoo! Alerts, I still tend to pop over into Google to investigate what's up and find more information for what I'm writing.