I'd like to join your forum, but a message saying "Please Join my Forum" isn't very persuasive. I think if you want to advertise your forum, you should put a link to it in your signature or pm a few of your friends. By the way, is your forum linked on any search engines? That might make it easier to find.
It just isn't very polite to advertise your forum on someone else's, and it probably won't get you any lasting members.
But hang in there and continue to make an effort! I'm sure you'll find a few loyal members in time.
Remember, this forum took a very long time before anyone came, and now it has over 2,000 members! Be patient, and with God's help and Divine Will, it will grow.