Search monetizes so well because there is so much implied intent in a search. But some have claimed slowing search volume and lowering ad costs.
The search box is perhaps the most profitable ad unit because consumers feel some level of control as they request ads about whatever topic they search for.
To offset slowing online adverting, Google is looking to “create” more search volume by using AdSense ad units to suggest consumers search for expensive keywords – like credit cards.
In the past Google has ran ads asking the consumer to “search for ads about ______” but this is the first Google ad unit that takes searchers directly off the publisher site and directly onto a Google search result with organic search results. It is one thing if Google asks for you to search for ads because they don’t understand the theme of a page, but it is quite another for them to have pre-made ads to siphon off the visitor to a Google search result without guaranteeing publisher payments (or is the first click paid, but at a heavily discounted rate?).
How much does Google pay AdSense publishers for this ad unit, when conversion happens after 2 clicks rather than 1? What percent of the end ad spend goes to the publisher when Google arbitrages the click through Google.com? How does smart pricing come into play when Google discounts the original click and then marks up the second one?
This sort of advertising allows Google to water down their search traffic slightly, but without advertisers knowing how it got watered down, or why their conversion rates lowered slightly.