We have been using Google adwords for over 2 years now and have always wondered if they actually do have a program in place to stop our competitors or other evil beings to click on our adds,.. Well we finally
did our own testing ,we chose a very inexpensive keyword with just 0.05 c and did click ourselves 10 times in 1 hour than 20 times ,.. here is what we have learned :

from 10 clicks in 1 hour ,6 registered and where charged ,from 20 clicks 11 where registered and charged ,..

that shows that they have some type of software to
sort out double use,but in my mind WAY to ineffective !!!!!!

Our company has 10 vacation rental sites and if any competitor has a student clicking away ,he can do mayor damage to us ,and that is exactly what we believe has happened to most of our spending within the last 2 years !

Please share your own knowledge and experience !

P.Binder

My experience is very similar but not as well documented as yours.

I find that I pay for more clicks to my sites then I have unique visitors. It's a small percentage overall though so I don't worry about it.

I let the math do the talking. If the math says I'm making money with this ad then I keep it. If the math says I'm losing money then I make a change.

-John

__________________
Selling your products and services on commission only. No upfront fees. www.historicfuture.com

Using open source tools for internet marketing including Linux Quanta Gentoo RedHat PHP MySQL, etc.