Alerts are an electronic tool for keeping up-to-date with changes in database (or other) content. In simple terms, they're notifications via email or rss feed that something you're interested in has been published or added to a database.
What's the point of setting up an alert?
If you've got an ongoing interest that you want to keep up with, even just for one semester, alerts can save you a substantial amount of time and effort. This "ongoing interest" can be topical - emergency room nursing, LL Bean, negritude in Caribbean literature - or it can be wanting to know when a specific article is cited, or what's in the latest issue of a favorite journal. Basically, if you can search it, you can turn it into an alert.
Most of our databases offer this feature. If you would like help figuring out whether alerts are available in a database not listed here, don't hesitate to ask!