Zero Tolerate Promoting and Marketing?

I am bit confused if this forum is a "zero promoting and marketing zone" given I seen just a few profile posts of doing this. So just clarification stakes...

Is it allowed in signatures and in profiles like some forums do allow you to have your own site's link(s) in it? Or is it "zero tolerate" policy?

Thanks in advance!

Communication Software for Deaf Hard of Hearing - NexTalk