Hmm...usually such stuff contain ads and are either click-rate
based or commission-based, so even if it is authentic, only the
first-level sender (not forwarders) gets the money. I mean, how are
they supposed to know who forwarded the e-mail which resulted in a
successful sale - one of the few ways to track is to append an
affiliate ID onto the URL linking to the destination page, which
would belong to the sender.
So, unless you feel like being a good samaritan for a day, chuck
that mail into the junk folder. It's just no better than a everyday
spam mail.