Targeting is something to think about when you are trying to maximize your results. It also might explain why you might be getting different results with the same splash page in different traffic exchanges and safelists. Pay attention to whether a traffic exchange is very social, having a social chat, and focused on user experience with prizes and themes because you would want to gear your ads towards that for success. An interesting example is click track profit badges. Many enjoy collecting them so you might get a personalized badge to go along with your ad to gain attention, hence you are targeting them. Maybe a more direct marketing message would work better in a different type of exchange. If there are a lot of cash prizes in a te or safelist maybe you would like to outline something about a cash prize in your ad.
Another interesting observation is that you might find better results in traffic exchanges or safelists that tend to be a part of your networking group. What a great reason to get to know more people and expand your networking group!