Sounds simple, making money by getting paid to refer, but is it really possible to make money by just referring people. Well the simple answer is yes you can. I came across this about 18 months ago and have been slowly but steadily seeing my earnings from it grow.
We all actually play a part in this chain. I'll give you an example:
Not so long ago I was spending a lot of time on Twitter and Facebook seeing what my buddies were up to, when one of them stated that they managed all their social profiles as well as all their email addresses in one easy desktop application called Digsby. I thought that was a pretty smart idea so I downloaded the free software and now use Digsby for handling all my social networking accounts.
Now even though I did not have to pay for Digsby my buddy who referred me was able to make money by referring me, so he was 'paid to refer', and there are 1000's of really useful software tools like that you can get paid from forseeing. Also there is a digital information warehouse that you can join for free, make money get paid to refer any of the 10'000's of the products and services that you refer of their. People can download whatever they buy straight way and you get paid money for referring them straight away too.
I know people who make 1000's a month getting paid to refer, and the ones that do not are the ones who think they are there to sell, selling does not work it's as simple as finding a group of people really eager for a solution say one on "how to train Labrador puppies" and then referring the to a digital product at ClickBank to solve their problems, it's a win win situation.
Affiliate marketers get paid a commission on everything they refer and it does not stop with digital downloadable products either, you can take a look at company's like Commission Junction, Linkshare or even Amazon just to name a few, and make money getting paid to refer tangible goods of all kinds, it really just depends on what your into.