BBC News - Why does Google+ insist on having your real name?

Check the story link below for a social network identity snapshot

So why do the social networks want your real identity? 

Google says it is addressing those with genuine complaints, but it maintains that to use the network effectively, users should be able to search for a friend or a family member as quickly and as easily as possible. And that, they say, means demanding real names.

Indeed, the guidelines are very similar to other social networks like Facebook and LinkedIn.

BBC News - Why does Google+ insist on having your real name?