Why do people post links to printable coupons?

I see this alot on here - some subject/question line that sounds a bit like someone involved in a Nigeran scam - and then you open up the discussion/question.

All that is in there are links to printable coupons and movies.

I realize it must be some sort of scam thingy as any "English" printed looks/writes like any Nigeran email scam, but what is the purpose of it?