IMO, marketing is important. Market your fighters properly on the net, it helps. But at the end of the day the product needs to speak for itself in the ring!
If you cant hang with the big boys, doesnt matter how many sites youre on or where youre promoting, this isnt the WWE.
Be active, get a site with some details on yourself and or other fighters, meet people, goto events and get involved in the community.
Thats my take, the internet is not really a free easy way, you still need to work at it.