Click fraud has been a big issue in both the past and present for these three, but these guys over time have managed to eliminate the majhority of the problem. This can't be said for most of the second tier search engines though. I don't have the exact stats on any one of these smaller search engines, so I won't make direct accusations at anyone, but I've read a lot of forum posts from individuals that are qualified enough to know what they're talking about.
If you are new to pay per click advertising I highly recommend that you buy a good book on the subject before you ever think of starting a campaign. Once you've done this, the best place to start is with Google Adwords. It only costs five dollars to start and the interface is fairly simple to learn. Good luck!
Does Google Adwords Have You Confused? There Are Important Things That You MUST Know About Google Adwords Before You Start Using It. Go Right Now To PayPerClickFirm.net or by clicking on Pay Per Click Search Engines. Joe Stewart is an Independant Internet Marketer That Uses Pay Per Click Advertising And SEOTo Advertise Online.

