I am also curious about the depth of options for this type of marketing. I see affiliate marketing everywhere, and there must be some profit being made by both the affiliates and site owners.
I believe that this can be a very crucial decision when determining revenue streams for an online business.
For example, on a membership based website, do you charge the members for access? Or, do you give members free access and charge the advertisers to have exposure to your members?
I think both avenues can be successful, and maybe a combination of them can also be successful. Are the members more committed if they are paying for your service? Will your customers be turned off by too many advertisements?
Just a few things that come up when I think of Affiliate Marketing. I guess I haven't really answered any questions, but would be curious to hear from anyone that may have gone through this decision process.
As always,
Wikipedia has a great deal of information on it.