The sites that appear at the top or on the side of the results page are usually those that have paid for there presence on the home page.
Step-by-step explanation:
It takes a fortune to list on the top or side of the search engine's result page (SERP). Presence on the top or side of the result page guarantees enhanced visibility and increased conversion chances.
The web content masters who are in the need of such strategic advantage often pay for it. The search engine such as Google, Yahoo charges them based on their preferences, content length and the target region. However, with adequate search optimisations, one can make his/her site appear on top in the search page list.