Well I have tried miva and im sure of click fraud and adwords is way to expensive. What are you using and what do you trust as a good ppc program other than yahoo or google cheers
I have only ever got results from Yahoo or Google. They are not expensive - people wouldn't bid unless the ROI was there.
It depends, generic terms are not profitable and dominated by big companies. But with highly targeted keyphrases, you can make money.
I agree, try to narrow your focus for the keywords you select. You may want to look at some tooles that you can use such as Overtures keyword tool to show you some variations that you may want to try that may not have as many high priced bids but which still get a decent amount of monthly searches. Hope this helps.