Put ads in the theme league classifieds where they belong, not in the SLB forums.

Don't expect to not play for years and then just reappear and have people want to join your league.  If you play in some people's leagues, they may want to play in yours.  If they have no idea who you are, why do they want you to be their commissioner?  If you have a great idea, you can get past this problem.  If you have virtually no idea except to raise the cap 2.5x from an OL and exclude a group of guys who probably are running 75% or more of all active teams in theme leagues, you'll be lucky to get 4 guys who want to join.