Google Plus - aprox 40 million users as of 9/25/11 I am just following up on research from Paul Allen https://plus.google.com/117388252776312694644/posts/bGJPTALDkDe http://news.ycombinator.com/item?id=2747710 I added a couple more recent samples (threw out a few names) 07/04/11 07/09/11 09/21/11 09/25/11 1,700,000 4,700,000 29,372,543 41,308,415 Maring 3 9 50 65 Tomczyk 5 20 165 219 Lagana 7 13 100 150 Shireman 2 12 43 59 Tat 12 51 Tozzi 15 31 175 247 Trudel 9 25 212 286 Yasin 25 52 Greb 3 11 Toepfer 3 13 68 79 Cullinane 7 18 80 100 Fredenburg 3 23 35 Louderback 4 38 53 Santillanes 3 29 45 Murrey 4 Wilcoxen 8 20 40 Revelle 5 Parten 3 Lewter 6 23 30 McTigue 9 49 61