Google have decided to retire Web alerts because they are used by very few people and an alert of type Everything will find the same results. Now Google web alerts will become everything alerts.
This week Google will be changing all alerts of type Web into alerts of type Everything. User’s alert will continue to include results from all kinds of web sites.
Google says, “You may receive more results after this change. If you find that you are getting too many results, you can change the "How often" setting to "once a day" or "once a week." You can also change your search query.
You can do this on the alerts management page (www.google.com/alerts/manage), or by removing the alert using the link at the bottom of each alert email and creating it again with different settings”.