One of the biggest online markets is the gaming (gambling industry) a Multi-Billion industry and with the explosion of poker along with mobile gaming this is certainly a market that many non-gaming sites can tap into with a simple banner or widget. There is no product to deliver, no stock needed and your earnings are ongoing.
What is VERY important is using a trusted client to provide to your customers, Betfair offers everything for the newcomer, second to none customer support and a fully operational backoffice that allows you to track your commissions and conversions.
At present they have what I consider one of the best deals ever and that is to give all new signups a free £25.00 bet, Should they lose they get their money back! This is a win win situation for both yourself and your customers.
Getting an affiliate account is simple (takes about 5 minutes) and they will provide you with all the media and support that you need to get started.
If anyone would like any pointers please let me know, I can also put you in touch with the affiliate manager who will give you the very best advice in generating a steady revenue from your site.