Pay to Click Advertising - Does it Work?

With so many pay to Click sites around at the moment I have wondered how useful pay to Click advertising was. I always assumed that Pay to Signup was much better value for money. However, as I have never tried it myself, I thought that I shoudl try it out. I had $0.40 worth of earning on Ads2View which is a pay to click site. I traded in the earnings for 160 pay to click adverts for Mediadollarz. During the time the advert was live I received 2 signups for Mediadollarz. This equates to $0.20 per signup which is what I pay for signups through Buyrefs.

I am now comtemplating whether it is worth advertising on one of the more expensive but more popular pay to click sites such as Adbux or Clixsense.