Even wonder what relevant link means?
As we are humans we almost instantly can figure out that there is some kind of relation between apple and banana. Relevance is a term used to describe how pertinent, connected, or applicable something is to a given matter(from wikipedia.org).
So how search engine (computer) knows the connection between apple and banana? Well … I have no idea, but there are many smart programmers at search engine industry.
All you have to know: all keyword falls under a category and the best links you can get is from the very same category.
Taking the search term – work from home – as example, simply paste it to Goole Insight: http://www.google.com/insights/search/
Google recognize this keyword as it is most relevant to Business category.
The very best backlinks for the search term – work from home – comes from business class websites. Links from computer&electronics, health, entertainment and society sites are also counted but with much less weight.
The point is: a business website has more authority to tell the search engine where the users may find useful and quality content about ‘work at home’, than a entertainment category website.
Other categories NOT listed above, has no authority to tell where to look for informations about that keyword.
