What is Link building?
Link Popularity refers to the number of links pointing TO your site FROM other sites on the Web. Building links is one of the most important factors in getting top placements on the major search engines.
Why are links so important?
Now these days, inbounds links are the one of most important factor for getting a high keyword ranking, the most search engines are ranking their search result on the link popularity from your site. Not the quantity from the links, but the quality of those links is important.
Building Link Popularity helps your Web site gain PageRank.
A higher PageRank enables your site to rank higher in Search Engines with competitive keywords. More and more major search engines, including Google, Yahoo, MSN, Ask Jeeves, AltaVista, etc. rely on off-page factors such as Link Popularity to determine how important your site is in order to rank it in search results.
Google pagerank explained
PageRank is the measure of importance Google assigns to a Web page on a scale of 1 to 10. You can check the PageRank value of every page you visit by downloading the Google Toolbar. Google’s founders, Sergey Brin and Larry Page, formulated a Search Engine algorithm that shifted the ranking weight to off-page factors. They developed a formula called PageRank, in which the algorithm counts the number of sites that link to a page and then assigns the page an importance score on a scale of 1-10. The higher the number and importance of sites that link to your page, the higher the PageRank of your Web site.
One-way links
To establish ‘only-incoming’ links also called ‘one-way links’ or ‘Non-Reciprocal links’. Only incoming links are the links established on the other websites where you do not need to link back to them.