Summary: PageRank isn’t the only thing that determines how valuable a link is. Relevance, authority and trust are also important factors.
So you understand the importance of getting good quality inbound links to your websites – ‘votes’ in the eyes of Google for the quality of your site. You’ve read over the page rank rules and understand how these work. At this stage, you might be thinking that sites with a high page rank are more valuable that sites with a low page rank. Is it really that simple? Unfortunately not. Three other factors need to be taken into account when considering how search engines will evaluate the links to your website.
If you obtain a link from a site that is about the same subject as your website, or a similar subject, that link will be more valuable to you than links from websites on an unrelated subject. Why?
Let’s say for example that your site is about fishing boats. If another site about fishing boats links to your site, the search engines will view that as additional confirmation that your site is relevant to fishing boats. It’s therefore a better ‘vote’. If the other site linking to you is about racing cars, no such thing happens. So, in short, getting links from sites that are relevant to yours is better than getting links from just any old site.
If you write articles on article websites like Ezines or social media posts, make sure your article relates to your site too, for the same reason – where the page is relevant to your site, the vote will be more valuable.
Some sites are considered by Google and other search engines as authoritative. There are sites you will find in relation to your own website topic, which are ‘hubs’ for particular subjects. These are niche sites that will contain quality content on the subject and usually a comprehensive collection of links to good sites covering the subject area.
There’s no list of these sites anywhere so it’s not easy to track them down (try SEO Moz’s ‘juicy link finder’ though: http://www.seomoz.org/link-finder). Naturally you’ll stumble across them as you’ll be looking for on-topic sites to gain relevant links. A good place to start is Google’s page rank for the site (get the Mozilla Firefox plug in if you don’t have it already!) and Yahoo Site Explorer which records back links to a particular site.
Of course you can make an educated common sense guess on what’s an authoritative site for a particular topic. A section of a respected newspaper devoted to a particular topic like the Times online is likely to be considered authoritative.
Obtaining links on authoritative sites is also tough – you can contact them and ask them for a link but they are authoritative because they’re experts on a particular topic and aren’t likely to link to just anyone.
Search engines ‘trust’ some sites more than others, although unlike our notion of trust, it’s thought that this is usually based on calculation. It has been suggested that some engines will look at which other trusted websites link to your site – links from trusted sites improve your trust score. Others are based on manual reviews of some trust sites and then a calculation of your trust score on the basis of how many clicks you are away from those trusted sites. Whilst nobody knows for sure whether Google uses a trust algorithm, it is widely accepted that they do – thus, be careful that you obtain only links from good quality sites and never from link farms or non-relevant, spammy sites.
It is interesting to note that you should also be careful which sites you link to – linking to spammy sites could in fact reduce your trust ranking (sometimes called ‘reverse trust rank’).
Are EDU and GOV links better?
Some people think that links from .edu or .gov domain names are ‘better’. But this view is not shared amongst SEO experts. The reason is that there are many blogs, forums and websites which spammers use to get links to their websites. The search engines can’t therefore allow automatic trust just because of that domain extension.
However, there are many trusted authoritative edu sites. Those sites are trusted because they are well linked to and have quality content. So the benefit of a link from these sites is because they are trusted and authoritative, not because they have an edu or gov domain extension.
When is it useful to get non relevant links?
Non relevant links aren’t entirely without value. They can bring you extra traffic. They can also contribute to your page rank, albeit not in the way that relevant links can. Perhaps most importantly, when you’re looking to get new content spidered, a non-relevant link can help the search engines to find your new page. This is especially true of new websites.