I got a prized early invite to Google+, the search giant’s highly anticipated Facebook competitor, thanks to the magic of Wired’s Steven Levy. But I could not find it anywhere.

Gmail, it turns out, decided the invite was a phishing attack and stuck it in the spam folder — where search doesn’t naturally reach — and slapped a giant red bar on the top, warning me it might not be from the sender the e-mail claimed to be from.

Gmail’s algorithm need not be so protective. Google+ turns out to be a well-designed social network, centered on the concept of Circles — the idea that relationships are more complicated than the binary friend-or-not-friend model that has served Facebook so well.