If you would like to display advertisements on your site you should choose Google AdSense, but I think you shall first study how to choose the best keywords in a niche. You can find a lot of free information about how to choose a niche and AdSense keywords by just searching in Google.
Google is not bad but it's very competitive now. You should look for alternative in affiliate networks.
Actually the click is not depend on the advertiser. Instead,its depend how you place the ads at your site.
making money via PPC ads doesn't really depend on the type of advertising program your using its all about the ad placement and content on your site, good luck
Adsense and Adbrite are good when you first start off right now im using Burst Media and they are pretty good
How can I give Microsoft ads ? And Adbrite or Burst Media needs social security number, I am from India
There are many alternatives available for google Adsense. You should try the link which is in my sign.
You can try CPM rather than PPC. Adsense does offer it. Also you can try with yahoo, microsoft which are not used to an extent like google.
Click is not depend on the advertiser.adsense, yahoo, microsfot, abrrite, clicksor, cpxinteractive, etc.