I don't "get it".
You young 'uns need to read up on your web history
GoTo was a search engine back in the day.GoTo Sells Positions
by Danny Sullivan, Search Engine Watch, 03-March-1998. Yes, 1998.
Search engine GoTo debuted its new pay-for-placement service on Feb. 21. It allows web site owners to bid for placement. Those willing to pay more can appear higher in the search results.
Pay-for-placement is not new. Open Text experimented with it in mid-1996, and numerous small search directories currently offer the ability to pay for a better ranking.
Despite this, the major search engines have avoided such a service. This is mainly because they see their results as akin to editorial copy. They aren't something that advertisers are supposed to influence. By allowing pay-for-placement, search engine users may begin to mistrust the results they receive. Such complaints helped cause Open Text to give up its experiment.
What was interesting was that to the right of these paid results was the amount that each click would cost the site, i.e. $.05, $0.49 - a transparency rather foreign today.
Google is a search engine here today. Getting your ads above Google search results
, Google AdWords Help, 16-October-2012.
...and your bid
When customers search on Google, ads can appear at the top of the page, on the side of the page, or on the bottom of the page. Only the highest ranking ads are eligible to show at the top of the page. Your ad's position on the page is determined by your Quality Score and your bid.
Yes, the ads above search query results have a different background BUT it is subtle and may not be apparent on many monitors. Many people have written about this, i.e. Is Google Intentionally Trying to Minimize the Fact that These are Ads?
by Mike Blumenthal, 31-January-2012.
Depending on the query Google properties may be mixed with the results although increasingly these are being moved within the right sidebar Knowledge Graph results which mostly link to Google pages.
From GoTo selling the top positions to Google not quite blending 'ads' that look like results on top is a difference of minor degree: the more things change the more they stay the same.