OKSocial provides donation-supported hosting of servers for the diaspora* distributed social network, which had 695,305 users worldwide (and growing ...) when I wrote this page (see the current stats for diaspora* on the-federation).
OKSocial servers do not have any advertising and do not collect or analyse any user information beyond what is necessary to provide high-quality access to the diaspora* network.
OKSocial hosts three categories of diaspora* servers:
Accounts on the public servers are free.
And as long as donations stay above the costs of running the system, OKSocial won't charge any fees for accounts on the community or private servers either; these servers may have fees if the donations from their local users aren't enough to meet the server's costs.
If, on the other hand, donations on a community or private server are higher than we need them to be, we'll pass the surplus to the sponsor of the server to do something nice for their moderators or whatever.