The only pay-per-click advertising I've ever paid for was through Adbrite. What I don't like is that their cost per click is just an estimate and is not necessarily true. Other alternative I've been considering were Adsense, Search Advertising, and Kanoodle. What do you think is the best pay-per-click advertising network to invest in and why?
I use Adbrite, but I look for the text links that are for sale for like a month...those are set priced and you can get some great deals
as always, it depends on your target and your goals. you also have to be very calculating when buying through adbrite (for example, you can pick up on the newer sites that you know are spiking in traffic that haven't been priced high yet). don't ever take their estimations with anything more than a grain of salt either. anyway, if you're looking into paid search marketing, my CPCs are always lower in Yahoo than in Google, and the quality is about the same. volume is lower in yahoo of course, but a high return is a high return no matter the volume. this is just my experience though.