The majority of web traffic is driven by the major commercial search engines such as Google, Yahoo and MSN. Google attracts approximately 60% of worldwide searches at 37 billion, with Yahoo (8.5 billion) and Microsoft (2.2 billion) (numbers taken from website). A number of country-specific search engine companies have also become prominent in their own territories; for example Baidu in China, Guruji in India, Yandex in Russia.
High placements invariably lead to sites receiving an increase in traffic. 78% of users abandoning their search if the first 3 pages don't provide an answer to their question high search engine placements are essential. 28% don't even consider scrolling past the 2nd page of results.
This is the reason why search engines prefer high traffic websites because favouring less traffic websites will in turn result in abandoning the search from that particular search engine and thus decreases the popularity of the search engine. Those 78% of users will not bother to visit the same search engine again because they knew the results of their earlier search. No search engine can carry this bad name with itself that is why high traffic websites are given top most priority.
Just think it on your own - when you search for the 'best ways to convert a PSD file to HTML' will you bother to look for the thousands of search results shown by the engine. NO . This would be your obvious answer. and the websites shown on the first three pages are the highest traffic caring websites indexed by the search engines.
High traffic can be converted to revenue through sales, advertising revenue, referrals, votes or whatever call to action is invoked on landing pages. Smart, professional Search Engine Optimisation yielding high organic returns (70% of search engine users prefer organic search returns to sponsored links or PPC) can deliver extremely powerful results.