Link building is one of the important factors in Search Engine Optimization. Both, the quantity and quality of backlinks to a site can impact its ranking in Google. When many high quality websites place your website's link on their web pages, then Google and other search engines take that in to account and calculate that the site must be important or popular and reflect that in search results. So in effect, inbound links to your site can influence your site's performance on search engine to a very great extent.

It's not just the number of inbound links that affect a site's visibility in search results. It's also the quality and the ways in which inbound links are secured that have say in search results.

Few years back, some clever people found out that they can game Google by creating link farms and reciprocal link exchange. This mechanism caught on and was widely misused. As a result, Google wisened up and tweaked its algorithm to discount or even penalize inbound links secured in such a manner. So while it's perfectly legal to actively cultivate co-operation with other useful relevant websites, don't over do this as Google can raise a flag.

Also, the growth in number of inbound links should not be steep. A sudden spurt in backlinks to your site with same anchor text can and will raise suspicions. Natural inbound links mostly have variations in anchor text and the text surrounding the links. Similar looking links can signal these links are not genuine. It's advisable to create a mix of inbound links with differences like anchor text, title tag etc. Also, while inbound links to home page is most advantageous, deep linking is also beneficial. Deep links mean links to inner pages of a website which may be services or product pages. Deep linking has a cumulative effect and boost's a websites rankings and traffic. This will make the inbound link patterns look more natural to search engines.

Links from authority sites with higher Google PageRank also carry more weightage. Try getting inbound links from sites with good credibility and PageRank. Google's algorithm gives large importance to pagerank factor. Researching any top ranking site will reveal that it has substantial links from sites with good PageRank.

Link builders also need to be wary about links with nofollow value for rel attribute. These links will not give any Google juice. Many ill-informed link builders place backlinks on even prominent sites which have a policy of links with nofollow values. Many popular social networking sites like Facebook and twitter have this policy. Google won't give any importance to these links.