Link popularity is a term used to describe the amount of links to one website from the rest of the internet. Link popularity is most commonly used when referring to search engines and search engine optimization, as link popularity is one of the most important factors in how search engines decide to rank web sites in the results pages of searches. The rationale behind this is that if your link popularity is high, and many people are linking to your site, then it must contain content and information that people find useful.
The most common example of how link popularity is factored into search engine results is Google's Page Rank. While most search engines use algorithms that include link popularity to determine search results, Google's Page Rank is of specific importance and significance. Google actually assigns web pages a numerical value that is a representation of their link popularity. A great deal of search engine marketing and link building strategy is designed to increase this Page Rank by increasing link popularity. This in turn can result in a higher position for web sites in search results.
However, in many cases there is more to link popularity than number of links to a site. Many search engine crawlers also factor in the quality of links into their determination of link popularity. For example, a site that has one-way inbound links from sites that are focused on similar content and contain similar keywords will be awarded more value by the crawlers than a site that has a lot of reciprocal links from non-related sites.
One killer for link popularity that many less knowledgeable web optimizers unfortunately still try to include in their is the use of Link Farms. These are merely groups of sites who agree to link to each other in an effort to artificially manipulate their link popularity to raise their position in search rankings. Most engines will actually penalize you for this practice now, so it's best to avoid.
Rather, focus on link building by submitting to web directories and cross linking between several sites that you own. Internal linking can also benefit your link popularity, and can be one of the most useful SEO tools.
Also, try to include keywords that have to do with your subject matter and content when submitting links. Text based links do much better than graphic links for link popularity, and if you can include keywords in them, it will be that much better for your SEO marketing plan.
And remember, crawlers do attribute more link popularity value to inbound links that they do reciprocal links, so building these are important. The best way to garner inbound links is to provide content that is informative, useful and of a quality that is unavailable in other locations. Providing good information will cause others to want to link to it, and this can be one of the best ways to inadvertently aid your search engine marketing plan.