As search engines become more sophisticated they have developed systems which look not just at the individual pages but also at other off site criteria such as the number of links pointing to your site. Building links with other web sites will increase traffic not just by making a higher ranking on search engines possible, but also from people following those links from other sites

Site Types
When considering link building strategies there are 3 identifiable types of web site.

1. Collecting Links
These are web sites, generally containing lots of unique content or popular tools, which people link to but the Collector site doesn't link back, they collect the incoming links. An example of a collector site would be www.microsoft.com which is a site with to which thousands of other sites link, but which only links back to a handful of related sites. When a visitor arrives at a collector site they will find lots of information but will be limited in how they can proceed further in their browsing without going back to another site, such as a search engine, to find more links.

2. Giving Links
A giver web site is one which contains lots of links to other sites but is not linked to by others. Browsing through one of these giver sites, you will have lots of opportunity to head off to many alternative web sites using the links provided. However, without links pointing to the giver site you are unlikely to find it in the first place. Personal home pages tend to be of this type.

3. Link Hub Sites
Web sites which have lots of incoming links from other sites and lots of outgoing links to others act as authority hubs on the Internet. They are easy to find and generally contain lots of useful content as well as allowing a browser to go elsewhere if they decide to. Hub sites aid the flow of people through the Internet helping them to find the information they require.

How Engines Treat Links
When search engines are assessing off page criteria such as links they look at a number of factors. The quantity and quality of links are gauged using mathematical algorithms. The number of links is one factor and the more the better is generally the case. However, the quality of links is also important.

Consider an example of a Bike Shop web site. If lots of other bike related sites link to the example site then the search engines can compare the theme of each one and make a judgment that our site is a valuable resource because other sites, with similar themes and visitors, have decided that it is worthwhile for their visitors to be offered a link to it. For links coming from sites about unrelated subjects, e.g. cars, then the theme of our site doesn't match the theme of the linking site which allows the search engine to give that link a lower value. They do this to avoid having to consider the thousands of Free For All link pages which are of little value.

The engines will also consider the text used to make the link. So if the link anchor text says 'Billys Bike Shop' it contains words which match the site theme so are considered to be more valuable than a link which uses just 'Billys' as the link text.

Combining these different factors allows the search engines to allocate a score which indicates the Hub Authority of any given site. By adding this score to their general ranking calculations they are able to return more relevant results to users.

So how do we go about increasing out Hub Authority?
Firstly consider how you want your links on other sites to look and write a piece of code which puts things in the right format. e.g.

This allows you to copy the link you want which includes your keywords inside the link text and to send it to potential webmasters asking them to link to your site. When approaching others asking for a link avoid having a standard request which you copy to everyone. Instead customise each request by saying for example that you have visited their site and liked the section about 'Buying Bike Clothing' and that you thought their visitors might be interested in also looking at your site which has complementary information. By making the request more personal you are likely to receive a higher response rate. Consider making a link to their site on your own before you send a message so that you are giving something rather than just taking from them. Always ask for a link to your site and include your code to make it easy for them.

Finding Sites to Link With
Identifying sites which are likely to be prepared to link to yours takes some research. To see which sites are linking to your competitors and look at directories such as www.yahoo.com and dmoz.org for related sites.

Once you have got a link from another site make sure that the page containing your link is also listed in the search engines. You may find that other sites link to you without asking. These can be identified by looking at the referrer information in your web site statistics or server logs and again these should be listed with the search engines.

Also consider a 'Link To Us' strategy such as the one at http://www.seoconsultingfirm.com/aboutus/linktous.html which offers a link back to your site and has pre-configured code for a selection of banners and links.

Building link popularity and swapping links has many benefits. People find your site through those links on other sites, your position on the search engines will be improved and your site will become more useful to your visitors allowing them to find more related content.