Google started their new service called Google+ which is the newest addition to their web toolkit collection. After the fail of Buzz and Wave (I'm sincerely missing the last one) this one stands a chance to survive and definitely shake the Facebook market.
Few hours of clicking around I was happy with the light version of network - the standard minimalistic design (total lack of any design according to some users) and lightweight platform unlike Wave. The invitation procedure that we know since GMail works as well - plenty of mediocre users wanted them to be _in_ only for the being special case. However.
A great review on the subject is the comparison of Plus with Wave and Buzz. I'm hitting the +1 on that one.