Hi Mike. It is really hard to calculate what server capabilities you need to handle a certain amount of members. It depends on the amount of content they upload, on how often they visit your site per day, how long do they state online and how active they're in communication. It is almost impossible to calculate those criteria.

What we can recommend is going with a VPS server for the first time (pick one of our recommended servers) and increase your powers as soon as you feel it is necessary. You would also want some skilled server administrator's assistance to maintain your server.

Got it. Thank you.