Shoutbox

I think that Microsoft finds out the the WhoIS information and compile a list of websites who are providing links to betas. Then they email that list to each host with the list of websites using that host who are providing those links. That saves time for Microsoft writing an individual letter to each author detailing where the breach has occurred.

I'm not disputing if it's right or wrong to go straight to the host to save time but that's what I think they do.