Inactive Members

The Facebook thing had me wondering I should maybe have a limit of inactivity.
I know a lot of people prefer to lurk but I'm thinking the point of the forum is to have everyone participate and contribute no?
What do you think?

I see the same people posting and I would love if everyone put in their 2 cents from time to time.
Not to mention the Facebook winners proved I may have to cancel memberships to keep the contests and exclusives fair for the actual participants of this group.

I want this to be a fun and fair group so I'm asking for YOUR suggestions.
SHOULD I cancel inactive members?
How long before I do that?

S.O.S