Referral traffic is off-site optimization and is the meat of SEO and is perhaps one of the most important components of SEM. Having a link building campaign that refers to many sites will generate traffic purely through people following the links. But perhaps even more critical is that the number and quality of links to your site is one of the principle factors such engines use to calculate your SERP. So you get two benefits: pure traffic and ranking in the search engines.

Google PageRank

Google particularly emphasizes how many sites link to yours, the most important criteria for ranking a website is its link popularity. But what exactly is link popularity and how can you get it? Put simply, link popularity represents the number of sites that link back to your website.

But how is this rank calculated? Quite simply, actually. Google's main criteria for the calculation of relevancy for a page is based on the number of websites that link back to that particular site.

How many sites are currently linking back to your website? If you don't know, it's easy to find out. Just go to google.com and type link:www.yoursite.com into the search box (replacing www.yoursite.com with the domain name of your website). Note that Google only displays a small percentage of the true backlink set for any given URL. You can get other estimates by doing the same thing on Yahoo! and MSN. When the search results are returned, look at the text on the right-hand side of the blue bar at the top of the page. It should look something like what's shown in Image below:

On that image shows that there are 411,000 websites linking back to this site. If there are only a handful linking back to your website, don't worry—by the end of this section you should be able to increase this number by 5, 10, 20, or even 100 times!

"How many websites should be linking to my site?" I hear you ask. As a general rule of thumb, you want as many sites linking back to your site as those linking back to the site in position #1 for one of your five keywords. Keep in mind that the rate of link growth is very important. Backlinks should be acquired at an even pace and should not be acquired all at once or within a short time frame. This sets off Google filters.

Take one of your five keywords/phrases that we worked out earlier and search for it on Google. Take the www part of the URL for the first search result of this keyword and find the number of websites that link to that website—this should be your goal for the number of websites linking back to yours.

For example, if one of your keywords were "baby names," and the first site that came up when you did a search for this keyword was www.babynames.com, then perform a link popularity check on this site by searching for link: www.babynames.com in Google.

When the search results page is displayed, look at the number after "about" in the text on the right-hand side of Figure 8.3. That's the number of sites linking back to this website, and it's also the number that you should be aiming for to link back to your website.

So how do you go about finding sites to link back to your website? Spy on your competition using PR Prowler (www.pr-prowler.com). This will tell you exactly who is linking to your competition and how.

As we saw earlier in this chapter, the most valuable links for your site are from other sites that are related by topic to yours. So if you have a site about baby names, a link from a site about baby health would be more valuable than one from a site about computers. So the challenge is not a need to find links, but to find links from sites that have a similar theme or topic to yours.

So to find them, as we just saw in the example, you can use a command link: in the search box to find sites linking to a particular URL. You can also use search engines to find websites that are related to a particular URL. The command to do this is "related:".

So you can go to Google and type in related:www.babynames.com, and that will find many sites that are related by topic to www.babynames.com. You can also use the related: command to find sites that are topically related to your competition.

So let's summarize where we are right now:

1. You find keywords by finding out how many people are searching for it and how muchcompetition they have using a tool such as yourseobook.com or wordtrackerkeywords.com.
2. Succeeding at SEO means you only have to beat your competition. Find out who theyare by searching with your keywords in Google.
3. Find out how many people are linking to the top results using the link command.That's how many links you need to rank to beat them.
4. Use the related command to find sites topically related to yours.

While these four steps are pretty labor-intensive, they are critical to achieving high search engine ranking. There are many software tools out there that can help automate this process. If this were a web document, this might be the place I would have a few affiliate links! Instead, in keeping with the idea of building a website on a low budget, there is a useful tool available for free called Webferret.