This is the second most important isssue on which people ask, next to website costing and maintenance. A good search result (to find a website or a webpage through keywords) helps in popularizing the site and increasing its utility to a great extent. There are a number of search engines on the web, but, over the last few years, Google has taken the position of almost monopoly on it. So, people are now mainly interested in the search result which Google shows compared to the other search engines.
There are various factors which control search results of a website or a webpage. One very important factor is, the amount of traffic (i.e., the number of hits to the site). Suppose a newcomer in some profession launches his website and another top celebrity in the same profession launches his website on the same day and from the same city using the same hosting server, but the newcomer announces his site in a big way through advertisement in a newspaper there but the celebrity site comes just as one line in a news in the same newspaper. Within 24 hours, the celebrity site may start showing at the top of the search result page with minimum keywords, but the newcomers site may take several months, and that too, may be below several similar results or on 2nd, 3rd, or more pages later.
For more details, please check at FAQ > Web & Internet > Search Engine Optimization (after going to each subsection, you can press the back button of your browser to return to this page).