There are many factors that make a link "powerful".

What are these factors it is a question that remains open to debate. You can even hear the word linkjuice , which is another term that refers to the perceived amount of power obtained from a link to its website. Said in simple terms, each link to a page is a vote, and the page with

the highest number of votes,
the content more relevant,

You will be winning and get the best placement in the SERP . Too simple? Not necessarily. Remember: not all links have an equal vote .

Some SEO experts say high-profile terms widely used as domain authority and theme of the site are not really factors that Google and other search engines take into account. It is said that the power of a site comes solely from its internal link structure, large amount of new contents and a lot of links pointing to it (including many deep-link ). That's why, say these experts, Wikipedia ranks so well. But it's so true? Not really, because considering the ' authority of the individual pages actually Wikipedia in many cases is quite poor.

I noticed, for example, a domain with a page main index PR3 that, according to my software control of links, has only two inbound links for the whole site. An inbound link is from a PR4 page and one from a PR0 page. However the homepage for both sites in which they appear these links have PR4. Do you follow me? Now, a link on a page PR4 is a powerful bond, but it should be sufficient to make such a domain PR3 (always if we rely on the studies of the logarithm determines the PageRank). But in this case it is so! What can we deduce? Perhaps the PR4 domain propagates also to its own page with PR0, if the domain is highly reliable. That is why I am convinced that the power and confidence of the global domain could affect the PR that you will receive from a link on a page.