Which is better to used Google Adwords, Yahoo Search Marketing and MSN Adcenter? Which will give better result for your site?
YSM is pretty nice. Google Adwords is OK, but the competition is very high. Haven't yet tried AdCenter. I heard that AdCenter's conversion rate is high but the traffic is low.
Generally speaking, I think Google AdWords is best. If you are just starting out and learning how to use pay per click, then I like to suggest Google AdWords. When you get into specifics and lots of detail, this is where you have to do some testing to see which one is better for your industry and keywords. They all have their advantages and disadvantages and they are not even across all niches.
Google has 8 times the volume of msn and yahoo combined. Yahoo is way bigger than msn, msn sucks ass, but hey they do have really targeted traffic, but super low volume.