How to prevent googlebot following links in gmail messages? Well bad news is “Googlebot is following links sent to subscribers of a mailing list by email and it is causing those subscribers to receive an unsubscribe meesage or a added download from the list or server”.
Bigger Bad news is that age old trick will NOT work here, we can not solve this simply by adding
<a href="signin.php" rel="nofollow">sign in</a>
Best way in my opinion is to reject download count based on the user agent. Which is Googlebot in case of Google Crawler.
find long answer here.