do anyone know a service for monitoring a webpage and notifying changes by email?

Question by A_user: do anyone know a service for monitoring a webpage and notifying changes by email?
i’m in need for a web service(not a desktop application) that monitor a predefined webpage and send me an email “containing a snapshot of the page or something like that” when the site changed,do you know such a service ?

many thanks in advance

Best answer:

Answer by Tony T
There is a free service available that does just that. See http://sitechanged.com/ for details.

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