By clicking this button, you can create an email alert, which notifies you for any new papers that may appear for the given query. You can use it:
- For normal queries, getting notifications for queries such as [author:lastname] or [intitle:titleword], or by any other query on Google Scholar
- For citation queries, getting information about new papers that cite a given paper. For that, you need to first go to the "Cited by X" page, and then click the alert icon.
At the end, you get a nice list of alerts that can notify you when new papers of a particular author appear on Google Scholar, when new papers about a topic get indexed, or when a paper gets cited (the almighty citation!). Here is how the alert list looks like:
I tries to find some official announcement for this feature and I could not find anything. Not sure if this is rolled out to everyone but it is certainly very very useful!
My Citation Tracker tool becomes less useful now, but I am glad that we will stop trying to implement this feature on top of Google Scholar and Google will start doing it natively. Next step Google: RSS alerts!