Originally Posted by jhonden
Google is definitely trying to increse its user base and moreover Google+ is more comprehensive and better then facebook and it has the ability to share more knowledge and education when compared to facebook perhaps this is the reason they have allowed children of 13 and above to subscribe.
It isn't about Google or Facebook sharing knowledge and education with children but about children sharing it with each other.
The point that Google makes in their statement is that whereas on Facebook anyone aged 13+ can interact freely with people of any age (and therefore perhaps be vulnerable), on Google+ there are safeguards as explained in their statement:
The reason why they have allowed teenagers to join is simply because they want more members.