We are creating Blog or Website for no other reason but to earn more money.

But this has been a major challenge for many Blogger in the market place because Google:

the major and the biggest in this system have become a thorn the in the flesh of many player in the market place,

by disqualifying accounts for different issues.  Visit- http://money-making-freetips..com/ to read more.

For how long have you been using them and how much have you earned so far?

Don't even try to use bidvertiser, the will only manage to pay you if your click is from a US ip or a forign country ip and they don't realy have advertisers. But you can give adbrite a try, they seem to have stipulated amount on your dairly page view, though they lack advertisers unlike google.

chitika is the way to go. Let me know if you need a unique account because i want to sell mine contact me via olicgad at gmail.com