One thing I'm doing that is different this time is putting Amazon modules onto my hubs.
So far I've made one Amazon sale from a hub from the first challenge, and none from any of the hubs in this challenge. I was about to throw my hands up and say that Amazon is a waste of time when I read a post by Ed Dale which says that you should make no decisions about a niche, website or affiliate product till you have got 200 visitors to it. Given that Hubpages shares the page impressions 60/40, this means getting 333 hits to it. And that is hits excluding reads from other hubbers, who don't really buy anything nor click on anything and only serve to inflate the stats.
By that criteria it's way too early to judge what is successful and what is not. I really need to stepup the backlinking to make sure that I do get sufficient traffic to assess whether I'm in the correct niches.