How do PPC networks Advertise themselves.

Hey DP members.
I am in need of your guys help here. I am doing my Economics project and we need to pick a product or service that we can get 10 advertisements for and work out if what they are doing is Price Competition or Non Price Competition…
Well anyway being the person I am. I’m considering choosing advertising networks ( service ).
Mainly focusing on Google and Yahoo here as they are 2 big wide known brands.
So how do these PPC networks go about advertising themselves? Apart from word of mouth/link on ads/brand name. ?
Have you seen any advertisements anywhere that you can recall? If so if you could link them that would be great.
( PS sorry mods if this is in the wrong section )

See original post by Aion