I have used safelists for promoting affiliate programs and I think that they are good for getting traffic. When using Google analytics you will be able to see the amount of visitors as well as the source. It is best to have traffic from a variety of sources such as paid ads to direct referrals as well as organic visitors. Plus make sure to choose quality lead generation websites that have "real" people on them instead of bots. Hope that helps. I have had great success with safelists but I only use the best ones.