Someone might e-mail you out of the blue with a translation of a website you control. They'll ask you to leave in the links to them as a way of giving them credit. The links are there to give PageRank to a shady SEO organization.
I admit, I came close to falling for this once, when someone offered to translate a documentation page I maintain into Romanian. But I have a friend who speaks Romanian, who read it and pointed out that it was the worst Romanian he had ever seen, and that was enough for me to look into what was really going on.