This assumes that the web page is written like a paper with well-defined topic sentences. Other search engines throw out tiny common words like an, a, and, it, and the. However, no matter how many different ways one searches for similar words, there is no context information, or a guarantee of relevance. The most common scheme is for web search services to rank their pages when you search. There are many different ways this has been tried and to varying degrees of success.
Some web crawlers use web page popularity as a search criteria.
If many people visit certain sites, they are probably more likely to be of interest to the general populace. This works well for hot topics and advertising, but works less well when more obscure technical data is being searched for. Another way that search engines rank pages is by how many links they find pointing to them. If someone else s page points to yours, maybe your page has something valuable on it. They use phrases of words and use user defined questions to hint at what context the document might be in.