What is Google Alerts?

What is Google Alerts?
Google Alerts is a service offered by search engine company Google which notifies its users by email (or as a feed) about the latest web and news pages of their choice.

Types of Google Alerts
Google currently offers six types of alert searches: "News", "Web", "Blogs", "Comprehensive", "Video" and "Groups". A News alert is an email that lets the user know if new articles make it into the top ten results of his/her Google News search. A Web alert is an email that lets the user know if new web pages appear in the top twenty results for his/her Google Web search. A News & Web alert is an email that lets the user know when new articles related to his/her search term make it into the top ten results for a Google News search or the top twenty results for a Google Web search. A Groups alert is an email that lets the user know if new posts make it into the top fifty results of his/her Google Groups search.

Google Alert Frequency of checks
Google Alerts also allow its users to determine the frequency in which checks are made for new results. Three options are available: "once a day", "once a week", or "as it happens". These options do not necessarily control how often they will receive alerts. The first option, for example, means they will receive at most one alert email per day. The "as it happens" option can result in many alert emails per day, depending on the search.