[mark6188]

Funny you should ask. I just posted a little about this in my blog yesterday.

It actually doesn't take much for me to join. A good review by a fellow webmaster like howlingwulf does on his blog is all it takes sometimes. Then I try to join via their referral link. Also I look at reputation/popularity as reported in forums like this one - particularly on payment history. Greenguyandjim publishes their stats on conversions, so I look at those to narrow my list of sponsors I want to consider.

After joining, the ease of which I can promote them depends on:

1. Quality free downloadable content (updated often)
2. List of top converting sites if they have several
3. Webmaster referral program
4. Variety of niches (a single niche is fine, but variety allows me to promote on more sites)

Trafficcashgold has pretty much nailed everything for me as an affiliate. Gammaecash also does a good job in the affiliate area. Other programs are close, but are usually missing one piece. For example: Topbucks is pretty good, except they require 2 sales before access to free content. Hard for me to promote them balls to the wall as a newbie when I don't have content for them.