Similar concept - PeopleAggregator

For people who belong to only one or two networks, signing up with an aggregation service may make little sense. But many people amass far more networks than that. SocialURL's founders say females who use the service belong to about 10 sites, while males belong to about half as many. "The average human will be a member of five to seven different networks," says Marc Canter, chief executive officer of Broadband Mechanics, which has a service called PeopleAggregator that connects various networks.

Overlaps of social media accounts

Many users have accounts on several different social networking sites. Alex Patriquin of Compete.com reported on the member overlap between various online social network services

Site	Bebo	Facebook	Friendster	Hi5	LinkedIn	MySpace	Ning	Orkut	Plaxo
Bebo	100	25	2	3	1	65	1	0	0
Facebook	4	100	2	2	2	64	1	1	9
Friendster	5	23	100	4	6	49	2	1	0
Hi5	7	24	4	100	1	69	0	2	0
LinkedIn	4	42	8	2	100	32	8	3	3
MySpace	3	20	1	1	0	100	0	0	0
Ning	6	35	6	1	19	44	100	2	2
Orkut	3	26	4	7	8	29	2	100	1
Plaxo	5	48	8	2	54	34	14	4	100

http://blog.compete.com/2007/11/12/connecting-the-social-graph-member-overlap-at-opensocial-and-facebook/