The block poster function is wonderful; I used it some time ago, and it turns out the Calgary forums are massively more readable without having some sicko interject his pathetic masturbatory fantasies over murder and mayhem at random.
To add a user to your ignore list, go to "User CP" in the upper left hand column, then find "Edit Ignore List", and type the names in. Really valuable, IMHO; some people have proven they are not interested in discussion, merely their ghoulish pleasure at the misfortune of others to further some sort of pathetic land use ideology.
I think this link may work:
edit ignore list.