said by voip_wire:The 10 users limit is probably in place a bit longer - I started using them in 2011 and 10 users limit was already in place.
You are right, the limit was changed to 10 users last year.
said by voip_wire:I would like to add though that this change portends North American calls with Google Voice will not remain free forever.
Google needs to decide what to do with Google Voice. Currently the service doesn't create any revenue for Google except for outgoing calls outside of North America.