Nowadays, search engines are placing more emphasis on incoming links to a website when evaluating rank. The main reason being is because they are difficult to obtain from trusted sources (a “by the book” website such as the Dmoz directory) and it is a great way to partially get rid of the group of people who abuse the “on the page” factors of optimisation (page spamming). How is this so? Well, if you have someone who is abusing the “on the page” factors and they have no trusted links to their page (they will most likely not get any at all as a result of spam) then there is no chance of them getting a good listing. However, individuals have worked out ways in getting a lot of links, through link farms as well as other tactics, no matter the quality of their website. As the search engines are aware of this, it brings us to the topic of how one link can be much better than ten.
Obtaining one link coming from a trusted source can be extremely difficult in the sense which they tend not to issue links to simply about anyone. If you have an excellent website with relevant information, then you will get them. It is for this reason one link from the trusted source can better a multiple of links using their company websites. As this is “trusted” by search engines like google, it will also trust the websites it links to. If you have ten links out of your best friends, it can help you in certain sense, but no where near just as much as usually the one link from a source like Dmoz, unless your friends has a very reputable website amongst search engines like google.
Having too many irrelevant links could harm your website’s visibility in search engines like google. Precisely what is meant with this is having links from websites which have no relation to yours. A good example of this could be a site about cars linking to another one site about medicine (unless the websites are reputable and have a good reason for that link i.e. there exists a relationship made between cars and medicine). Search engine listings will pick-up on this kind of link and definately will provide no weight in increasing your visibility. Obtain most of these irrelevant links, then djglva might be seen as spam (just like a link farm tactic) which will lower the popularity of your website within search engines like google.
The real key the following is to focus on quality rather than quantity. Gaining several good / relevant links will require you much further than a lot of irrelevant links. To get these quality links, get started by placing your site in directories, but make sure you avoid any “on the page” spamming because this is not going to get you accepted. Once search engines like google have acknowledged a presence of relevant links, followup on it and research some ways to get more. Over the years, you will notice that your website’s performance increases, since the links age, provided you may have performed internet search engine optimisation. Avoid obtaining the irrelevant links though it could be tempting to find out fast results. It are only a matter of time before an internet search engine realises the spam tactic, and as the saying goes “fast rise”, fast fall”.