Soft cap
From Hattrick
A soft cap is the idea of a rough limit on fans in each HT Team's fan club. As fan club sizes reach this soft cap, the rate at which new fans sign up to the club slows, eventually diminishing to a trickle of a few fans. The exact soft cap numbers are presently unknown; however, each Division level (Div III, IV etc) has a higher figure than the division below it.
A study of sign-up rate vs. current fan club size has been performed: Soft cap study (not in English).
