If this is true, then any website could use this same method to access Gmail contacts if you happen to have Gmail open in the same browser session.
Seems unlikely that it really works this way, it would be a huge security hole - spammers and scammers would be using this all the time to harvest addresses.
I'm also skeptical but believe it isn't coincidental that when I signed up, it recommended some people from my Gmail account. I had my country and city set as Beijing, China. The only other recommendations were from people in that area, I didn't know, because I'm really in the U.S.
Seems unlikely that it really works this way, it would be a huge security hole - spammers and scammers would be using this all the time to harvest addresses.