Links are important to Google, Yahoo and MSN in determining where your site is placed within the search results. As you probably know, the more links, the better you will place.
The engines place a weighting factor on each link. That is, a link from an important site like CNN.com would count for a lot more than Jimmy Bob's personal homepage.
Google calls its importance-scoring system "PageRank," and it's been a fundamental building block of Google's ranking algorithm since day one. Tactically improving the PageRank—or, more generically, your "link gain" across all the major engines—of your homepage and of key internal pages of your site is critical to being well-ranked and thus getting traffic.
Links are the currency of the Web, so it is important to have a plan in place to improve the number and quality of the links to your site from the outside. That is the idea behind link building.
Link building can be approached a number of ways. You can, for example:
- Garner links from vendors, clients, business partners
- Garner links from other related sites
- Garner links through general directory entries, like Yahoo
- Garner links through specific directory entries, like a marketing services directory if you are a marketing consultancy
- Sponsor organizations and get acknowledgement through a link from their Web sites
- Create content and syndicate through RSS so that other sites will post the content contained within your RSS feed on their sites with a link back to your site.
It is not just about the importance of the page, or the PageRank score. You probably get bonus points for a link from a topically relevant or authoritative site, so target topically relevant sites in particular when link building.
By the way, the worst kind of link building is sending unsolicited email to Web masters asking for a reciprocal link. Web masters get inundated with such spam daily.
Each page within a Web site is assigned its own PageRank score by Google. PageRank scores run from 0 to 10 on a logarithmic scale, meaning that the gaps between the integers increase logarithmically the closer you get to 10. So, for example, the gap between the 3 and a 4 is quite small, whereas the gap between 7 and 8 is huge in comparison. As such, boosting your PageRank from a 3 to 4 would be quite easy, and going from a 7 to 8 would be quite hard. Another logarithmic scale you might be familiar with is the Richter scale. As you probably know, a 5.0 on the Richter scale isn't such a huge deal, whereas a 7.0 is a very big deal indeed.