What is Google Alerts?
Google Alerts is a free notification service that allows users to monitor the web for articles, videos, books, and online forum posts containing specific keywords. It is owned by Google. 
SEOs and businesses use Google Alerts to monitor their brand mentions or competitors’ brand mentions. They can also use it to monitor keywords of interest, particularly those specific to their industry.
Users can create an alert by navigating to the Google Alerts setup page. The page contains settings, that would allow the user to specify the frequency of the alert, the time it should be sent, and the email address to which it should be sent.
Once done, the Google Alerts service will send out email notifications whenever Google indexes new content containing the keywords that are being monitored.