An interesting little tidbit from AdWords’ Enhance your ad using extensions page, regarding sitelink extensions:
You can add any or all of this extra information to your ads at no extra cost. Yes, free! AdWords only charges you for each click within the ad and its extensions, up to two clicks per impression. You aren’t charged for clicks on review extensions.
So, aside from reviews, you could pay that CPC twice for your ad, if for instance you have the commonly used sitelinks active:
1 click on the headline + 1 click on a sitelink = 2*(CPC)!
How’s that no extra cost?
Too bad: the new and improved sitelinks seemed like a win when they came out, what with the flexibility to be placed in unique combos on each ad group within a campaign, etc. Seemed like a no-brainer to add these to all ad groups & campaigns – but perhaps as the saying goes: no good deed goes unpunished!
Now I’m curious as to how these potential 2nd clicks impact CTR (click-through rate) reporting…