I wanted to build a website where I have a pay-per-click feature, like adsense, on it. But, am I allowed to have more than one pay-per-click feature on a website at one time?
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I have not seen specific non-compete terms, typically one would mix different ad types for optimal returns, perhaps adsense, banner ads, affiliate links embedded in promotional articles. If you have huge traffic adding kontera would add a few bucks.
Traffic volume is an issue for small sites running adwords, which might need perhaps 50,000 to 100,000 visitors to earn the $100 min payout, that issue is the main reason some small timers use alternatives to adsense, like Bidvertiser with lower payouts.
Yeah you can have as many as you want on as many pages as you want.