Its a new way of spamming I think...lol
It's quite clever really....The forum moderators/owners don't ban them because they dont know about them because they don't post.
They put up links to their businesses/websites in their profiles which Google does index and they get a small benefit to their site in question.
It's hard to explain...lol....Ok Imagine you cured cancer and started a website about how to do it. You would get a million/trillion websites linking to your site showing how to cure cancer.
Your site would rank number 1 for "how to cure cancer" because you have a million/trillion people pointing links to your site mentioning how you can cure cancer.
So...
Links to bank loans, cash loans sites on a thousand websites...If someone types into Google "cash loans" or "bank loans" or Fast loans, etc then by them doing this on thousands of forums their website will rank higher then it would of if they didnt do this.
Above is a half assed explanation and there are a zillion other algorithms and ways to do this but that is the basic explanation.

