Click through data is a huge part of AdWords since it's the most influential factor in quality score of the ads (it's a signal of relevancy) which helps decrease minimum bids and increase ad rank relative to the competitive landscape. An advertiser wouldn't want to game this aspect of it because they would have to pay per click to help themselves out, which would ultimately hurt them financially and they would spend themselves into oblivion (especially in highly competitive keyword markets; some of my keywords are $30 per click!).
Organic results use other signals for ranking including keyword density on page, cross links, and inbound links. Inbound links are the most helpful. Clicks may be a small part if they're anything at all, because that could be easily gamed. There are supposedly hundreds of factors that go into the search algo, but there are well documented methods to gain ranks, and they're true from my own experience of doing this for three years now, if you optimize the on-page elements, use anchor text well when cross linking, and you have a healthy amount and variety of inbound links.