I'm looking for a way of buying (cheap) traffic for hundreds of content pages on my site. Ideally I'd like a service that would allow me to provide a datafeed of urls I'd like to buy traffic for and it would use content matching to automatically determine where to display the ads. Does such a service exist?
Not 100% targeted to what you want, but close enough. Try Google Adwords. You can set up campaigns for different urls and your campaigns is shown on the pages that have similar content to your ad making them targeted.