Google Alerts is a service from Google that allows you to enter a certain search term and you get an email daily (or how ever you set up your notification settings) telling you of new results for that search term. A good way to use this is to see when people are talking about something you are interested in.
For example, supposed I wanted to see new articles online for Disqus and Disqus 2012. What I do is have two seperate alerts for each one, and I have notifications set so that I get one email every day with new results. If I want to see if any site mentions the term “Techman's World”, then all I have to do is make an alert for Techman's World. It is a good way of seeing if anyone mentions your site.
I'm not sure if Bing has something similar, but for now the only system that I know that delivers alerts like this is Google. If you know anything about what Bing offers in competition to this, then please do me a favor and post that in the comments below.
My current alerts are below.