For the average search engine optimisation company, building backlinks (incoming links) is a large part of the job. Although the internal architecture of your site is important for SEO purposes, it doesn’t tell the search engines how trusted it is to others.

Building backlinks is essential to your search engine optimization strategy, as tools like PageRank look upon inbound links as proof your site is trustworthy. The wider and more diverse your network of backlinks, the higher up the rankings your site pages will appear on searches. Some site owners are lucky, and get a high number of natural inbound links. However, most supplement this by putting additional links in places like internet forums, directories and news sites like Digg.

Some site owners use underhand methods, such as link farming ( where websites simply exchange reciprocal traffic to increase their search engine optimisation) and interlinking (the same thing, but where the linked domains belong to the same owner) Some search engine reputation management firms even offer link exchange programs, where site owners are duped into paying to have their pages given "high profile" on websites.

The theory is that the more sites your own site links to, the higher up the search rankings you will go. In fact, link farms usually have little to do with your business area – they’re just lists of links to other sites. Using methods like these is a sure way for you to lose domain trust - the worst thing you can do for search engine optimization. Other ways for you to damage your online reputation is by linking up to spam sites, posting in sites that are known to have illegal content, and bulk purchasing of links.

As we’ve said, the major search engines look very carefully at people’s SEO linkbuilding strategies, and place heavy penalties on sites that indulge in link-farming and other scams. Google is even working on ways to ban sites that engage in these practices – you have been warned.

To get quality backlinks, you first need to find the best places to post them. Backlink Builder is one of several useful SEO tools that professionals use to help locate suitable linking sites. They simply enter their keywords, and in return they get a list of sites where they can post blog entries, articles, reviews, videos or bookmarks to clients' sites. From these, they can then select those that best match the profile of the sites. The listed domains usually give their services for free – it’s a saprophytic relationship. They get content for their sites, and you get backlinks to your own.

Of course, you have to be honest, and make sure the sites you are posting to are similarly respected. Don’t post fake links to worthless content – and do check your links actually work! The last is easily dealt with, if you use an SEO company that offers linkbuilding services. Building worthy content that people want to link to takes time and effort, so the more you can offload onto other shoulders, the better.