Originally posted here by XNikon
I think I read there, that google uses a method that doesn't allow spammers to know the account is "active" when we click on a link. Isn't that great after all??
I think what they will do is block the HTTP_REFERER field and also not load remote images. That way, if someone sends you spam with an image linked to your email address, it won't load and so they won't know that your account is active. A similar thing applies to if you click on any of the links, except the referer field is masked instead.