It's the hottest invitation in technology right now -- an e-mail telling  you how to "learn more about Google+." If you get one, though, be  careful about clicking on it. It may be spam.
 
 Security vendor Sophos says that pharmaceutical spammers have recently  started to cash in on the popularity of Google's Facebook alternative by  pushing out fake invitations to the Google+ social service.
 
 "The messages look similar to the real emails that users may receive  from friends who are already members of Google+," wrote Sophos Senior  Technology Consultant Graham Cluley in a Friday blog post.  "However, clicking on the links will not take you to the new social  network, but instead take you to a pharmacy website set up to sell the  likes of Viagra, Cialis and Levitra."
 
 Google introduced its new service on Tuesday. Early members were encouraged to invite their friends, but on Wednesday Google stopped adding new members because of the "insane demand," according to Vic Gundotra, the senior vice president of Google's social media group.
 
 Spammers are always looking to cash in on the latest news trends, but  with these fake Google+ invites, they've lucked into an ideal scam. Many  people are eager to click on Google+ to see exactly what the service is  all about.
 
 "The spammers are no doubt hoping that the email will be too hard to  resist for many people eager to see Google's new social network,  although just how many users will be tempted to buy drugs online is a  mystery," said Cluley.
