I've got 10 at home (really 7 but 2 HT and one DC), 20 at my office, 11 at affiliated offices, one friend added 14 (or more), another 6. Many other friends with one computer. My son has borged every lattop (with permission) in the 1-61 CAV that he touched, all his friends from college fold for ChasR. And beleive it or not, I stay in touch with almost all of these folks and their computers. I also serve as their IT support guy from time to time.
Age makes a difference in convincing folks to fold. My 50ish friends are worried about many of the diseases FAH is working on. We have friends suffering from cancer, Alzheimers, etc. and we have kids that FAH will certainly benefit. These friends also have resources and can afford the electricity. So, they're relatively easy to convince and they generally don't ever notice FAH is running (no gamers).
Currently I have 107 active cpus in the last 50 days, 93 in the last 7. I turned off all the legacy rigs so the 107 will come down a bit but won't affect the 7 day count.