If you've done any research on search engine optimization, you've no doubt seen the word "algorithm" as part of an explanation about how search engines prioritize or rank results. So what is an algorithm?
It can take many forms, but an algorithm is basically a formula or step by step process. For example, a mathematical algorithm tells you how to solve a mathematical problem. It tells you what action to do first, what to next, etc. until you have the answer. A cooking recipe is also an algorithm. It tells you what actions to take to result in a batch of muffins.
Google uses not one, but many algorithms to determine the ranking of web sites in response to a search, deciding which one is at the top of the first page, and all the way to page 10 and beyond. While no one knows exactly what those algorithms are, we can give you a fictitious and simplistic example just for understanding's sake.
You type in "dog walkers" in hope of finding an experienced and reputable person to go into your apartment mid-day and take Fido out for a walk and bathroom break.
Google searches its index and finds all the web pages with "dog" and all the web pages with "walkers."
Algorithm #1 knocks out all the pages that have "dog" but not "walker" and vice versa. Its job is to get you the right information, not just match the two words, giving you a confusing list of results about dog breeding and devices to help seniors walk without tripping.
Algorithm #2 looks at where the phrase "dog walker" appears on the shorter list of web pages. Is it part of the URL, as in www.abbotsforddogwalker.com? Is it in a page title, like "Our Dog Walkers' Qualifications?" Does it appear only in the text? Let's say this narrows the list down to only pages where the term appears in all three locations.
Algorithm #3 takes a different perspective all together, and looks at information it has about the searcher. It knows that the searcher is in Vancouver, and likely knows the neighbourhood too. It also knows that yesterday, the searcher was looking for rain gear for large dogs. Since our list has 125 pages for dog walker in Vancouver, it drops all the rest. Of those 125, four specifically mention large dogs. Those go to the top of list.
And on it goes, looking at hundreds of factors, identifying and dropping spamming sites, raising the ranking of sites with high quality content (more on that next time), and the ones that are linked from other relevant and quality web sites (e.g. a local dog association or the SPCA).
All of that to say, you can't get to the top of the results list with words alone.