As the number of websites grow everyday, it is becoming increasingly difficult for a new site to attain good rankings on search engines. Since major search engines factor link popularity heavily into their ranking algorithms, building relevant links to your site is perhaps the single most important component of search engine optimization.

For a new site with no or few inbound links, buying text links on more established related sites could provide a boost to your link popularity. But this strategy could prove prohibitively expensive, especially in a highly competitive market where you'd have to buy lots of links to catch up with the competition.

Web directory listing represents a viable alternative to link buying. Apart from driving traffic to your site through direct referrals, web directories provide one-way inbound links to your site, boosting your link popularity and ultimately improving your search rankings.

There are thousands of web directories on the net, with dozens sprouting up every day. Some are general directories; others cater to specific niches. Some are free; others charge inclusion fees. Some are free only if you provide a reciprocal link in return. Many feature both free and paid listings.

The main advantage of a paid listing is the luxury of having your site listed quickly above everyone else's. Free submissions may take several weeks or months for review. If you work on a limited budget, you may want to submit to a handful of paid directories and a few hundred free ones.

Some directories charge inclusion fees that are too high for the listing to be cost effective. When considering a paid listing, look at not only the Google PageRank of the homepage of directory, but also that of the subpage where your link will actually reside. While it may seem like a good deal to have your site listed on a PR5 directory for 15, the offer becomes far less attractive when you find out that the internal page where your link is placed is only PR2.

If you've ever submitted to web directories before, I don't have to convince you that the process is extremely tedious and time-consuming, especially when you submit to a large number of them. Unlike search engines that send out robots to index web pages, web directories rely on more detailed submission forms to gather information about your site. Since each submitted site must be reviewed by a real person, most directories require that submissions are also performed by a real person, as opposed to an automatic script. Many directories use a visual code verification process to prevent automated submissions. Apart from complying with the directory's guidelines, manual submission is the only way to ensure that your site is submitted to the proper category.

Because of the time involved in manually submitting your site and the sheer number of directories on the web, it's important that you know which directories to submit to. Obviously, you'd want to submit to only the high-PR directories and avoid the low-PR ones, right? Not really. Just because a directory has a low PR does not mean that it's not worth submitting to. The directory may be brand new and has not been around long enough to be ranked by Google. In contrast to the more established directories that continually experience a back-log of submissions, newer directories tend to review and list sites more quickly. As the directory becomes more popular, so will your link. So, don't judge a directory solely by its PageRank; rather, base your decision on the overall quality of the directory.

Another important thing to look at is whether or not the directory you submit to is search engine friendly. Search engines like static web pages whose contents stay the same regardless of who visits the page, or when they visit, not dynamic pages that are created on-the-fly. Browse to a couple of categories and look at URL in the navigation bar. If the URL looks like, http://www.godirectory.org/links.php'ax=list&sub=42&cat_id=245, it's probably not search engine friendly. An example of a static, search engine friendly URL is http://www.godirectory.org/dir/713/index.html (notice the ".html" suffix).

Another question to ask is: How easy it is to submit to the directory? How many hoops do you have to jump through to get to the submission form? When you finally get to the form, how many fields does the form have? A directory should ask for pertinent information like your name, email, URL, link title, link description, and keywords, but it should not look like a job application. With the exception of a handful of major directories like DMOZ and Yahoo, you should not have to spend more than 3 to 4 minutes to submit your site.

Another consideration is whether or not the directory has a category specific enough for your site. For optimal SEO benefits from your listing, your link should grouped under a specific category containing sites whose contents are related to yours. Such a grouping makes your listing more relevant in the eyes of the search engines, as well as providing an easier way for visitors to the directory to find your site.

Simply having your site listed on a directory is not enough. Your choice of the link title can determine how much impact your listing will have on your search engine rankings. Ideally, your link title (or "anchor text") should contain the keywords that you want others to search for to get to your site. Since most web directories require a unique link title, however, it may not be possible to select a common phrase like "Free Web Directory" as your link title. This title is likely already taken by another web directory. Simply prefixing the phrase with your domain name, e.g. "GoDirectory.org Free Web Directory", would make the title unique.

Oftentimes, a directory would have several related categories that are suitable for your site. How do you decide which one to submit to? Ideally, you'd want to submit to the category that has the highest PageRank. However, this may not turn out to be the wisest choice as your link may be buried among a zillion other listings. Going with a lower-PR category with fewer competing links may prove to be more beneficial. When choosing from multiple related categories, choose one with a good balance of relevancy, Pagerank, number of competing listings.

In sum, submitting to web directories is a highly effective link building strategy that should be an integral part of any search engine optimization campaign. Manually submitting to a large number of directories is both laborious and time-consuming. Just keep the above points in mind to make the most of your time.