active games can the site support at a time? tia

The number of active games the site can support is simply down to storage space in the database. The more appropriate question is how many moves can be made in a second or minute by different players. That is limited by memory, cpu and disk speed of the host server. Even with the very limited hardware resources assigned to this site it's safe to say current loads haven't even scratched the surface of capacity. Load averages are typically at or below 0.01. More cloud resources are available at the click of a button (and with credit card details provided... :-) )