We have developed a Virtual Earth based mapping site that uses an IHttpHandler ASHX to generate pushpins. A major concern that we've been unable to find an answer for is how to restrict access to the ASHX to our own ASP.NET application to prevent data farming.
Whenever the map view changes, the client's browser will submit an ASHX call, which returns an XML set from our database to build the pushpins with. Since this call is originating on the client's computer, we're concerned a malicious user could set up a bot to submit these same ASHX calls, just changing the long/lat and parse the XML sets being returned. By doing this, the bot could generate a daily farming of all of our data and store it in their own database - to set up their own version of our site.
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