There are 2 settings you can choose once you have selected to link your account to Facebook:
- Auto post to Facebook when you attend/book an activity
- Auto post to Facebook when you amend your Favourites
These let your friends see what you're up to and then (when the jealousy bubbles over) join up themselves!
To turn these on/off just visit 'My Account' and select 'Auto-share' tools like below.