1. Dynamic algorithm- I think this is the main factor on why people preferred to use Google to do searching. Google has ability to change their algorithm from time to time, to benefits of the users. The dynamic of the algorithm will give more option and freedom among the website especially new created website to compete with those well established website
2. Page rank- Google has their own formula to rank website based on their Page rank. The Page rank in one way or another is another factor that google use to rank the webiste. The Rank is start from 0-10 where 10 is the best
3. Link Popularity – Link Popularity is refer to the backlink that website is receiving. It is kind of voting system to the website and google do take this into their account when listing the web
4. Content- Content is another influence factor. Do right a good content to get best results on the search engine
5. Website structure- Design and implement friendly SEO of the website. Try to avoid broken link.