Google don't like affiliates and they don't like the following at all.
-price comparision
-ppc affiliates (eg ppc partner sites, esp YSM)
-cpa affiliates with thin ( and not so thin sites )
There are exceptions, brand and size of operation play a role, MoneySupermarket etc is really just a big affiliate site but have a lot of suplimentary content and reach - read useful experience, you can't compete with their presence thats why their ads still run.
Even effective arbitrage sites that have real content running sponsoreds are not getting away with it except for Google bum buddy ASK.com who have no landing page content at all but they have both brand and are a Google search partner (someone with clout should REALLY call the press over that) tut tut TUT! because that is blatant abuse of fair competition and totally invalidates the supposed reasons for Adwords QS.
However its not just tiny weenie affiliates who Google are squashing, for what I think is one of the best reads of the week, have a browse over this little article,
its all about a company called Geosign and what happens when you wake up and find Google no longer like you!
You won't like what you read but what it will do is encourage you even more to look away from Adwords as much as possible for income and traffic because whatever variant of aff marketing you use, with just Adwords you are very vunerable.
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