I own a webmasters discussions forum and I just noticed that one of our member has links to "Viagra and Online Pharmacy" links in his signature. Now these sites are totally irrelevant to webmasters niche, do these links can hurt our forum's ranking because the links are going out from OUR forum??
I certain would not allow it since Ive seen my sites lose their link value from the amount of irrelevant outbound links.
You should not allow it. I am not sure about it but it is obvious that linking to irrelevant sites is not good