Per computer? That would mean taking note of the MAC address of the machine being used to log on.
It would be much more likely that they are logging the ip address - which then doesn't actually restrict to "per computer", hubby and I could both have valid accounts and one of us would be unable to use our 90 minutes because we would come from the same ip address.
However, given that hubby and I have at least 8 computers between us, restricting to one 90 min session per comuter wouldn't really work either...
Moot point from me as I have a full sub (and just one account) anyway, just curious as to the technical details behind the "per computer" criteria.