When we’re evaluating potential link partners for our clients, one of the key things we look at is whether they are in the business of selling links. The last thing we want to do is expend our resources targeting websites that might pass little or no value, because they are obviously selling links without using nofollow. The chances are, if you are confidently able to determine that a given website is selling links just by looking at it, the search engines will also be able tell and thereby nullify any value passed.
Bear in mind that Google doesn’t need to be too concerned about making mistakes when doing such a classification – as long as they penalise link sellers (by stopping them from passing value) they don’t risk excluding sites unfairly.
make sure your links don't look like this
Here’s just a few of the many signals we look at to determine if a site is selling links:
Look out for Blocks of Links
Some websites are less savvy about Google’s terms than others. Whilst it may be against Google T&C’s to sell links (unless using nofollow) many webmasters are unaware of this and don’t go to a great deal of effort to disguise the fact that they are selling links. They will therefore mark up the section ‘Sponsored Links’ or something equally blatant. This is extremely easy for either a manual reviewer or an algorithm to spot. If you are familiar with HTML, you can also check the source of any link blocks to look for clues in the markup if you see something like ‘div id=’ads”, then you have another clue 
Another obvious signal is where you find a block of links, often in a dubious place on the website (e.g the footer), that all link to a set of seemingly unconnected but commercial websites. A key thing to differentiate here is a ‘Blogroll’ from a block of ad-links – a Blogroll will usually link out to useful resources which tend to be a mix of other blogs, commercial and non commercial links – a block of ads will link purely to commercial websites.
Check the Anchor Text
Another obvious signal is in the anchor text of links – i.e. the text you see on the screen for the link. If all the links say things like ‘Credit Cards’, ‘Car Insurance’ etc, then there’s a str0ng possibility somebody paid for the website to link with favourable text – this is especially likely to be the case if:
a) the site being linked to isn’t called ‘Credit Cards’ (i.e. doesn’t have the url www.creditcards.com)
b) the site being linked is obviously targeting ‘Credit Cards’ as a keyword
Who are they linking to?
Possibly my favourite test of all when looking at a website’s outbound links is to see exactly who they are linking to. Generally, you can identify the major link buyers in any industry – the types that have chunky five figure link building budgets that buy rich links from anywhere and everywhere. If the website you are looking at links out to these (especially with rich anchor text in a sidebar) then it’s almost certain they are in the business of selling links – Google knows who the major offenders of link buying are, and therefore by association has a good idea of who the sellers are too – don’t get yourself involved with this crowd because you’ll probably be wasting your time/money… or worse, you may see a your site penalised.
Who owns the website?
Although this might lead to an occasional false negative, the owner of the website can give you a good clue as to their intentions. There are two interesting things to look out for here:
1) Is the website owned by a publishing company? If so, you can almost certainly buy a link. Generally speaking links tends to be nofollowed and go through some sort of tracking url. However, some publishing companies have wised up to the potential income from followed links…
2) Is there a disconnect between the websites owner details and their audience? For example is the website targeting a UK audience but owned by an individual outside the UK who also owns 572 other domains. Why should this concern you? Because there are literally thousands if not millions of websites created every day, purely to sell links to other countries. Although there will sometimes be a perfectly legitimate reason why the domain owner is overseas, it’s just another indicator that the website was created with the intention of selling links which can be balanced against other signs and signals.
Use your common sense!
It might be difficult to see every link on a page, but given you can pretty much ignore internal links for this purpose, scan your mouse over all the main link blocks and pay attention to the external links – a simple sense check can often tell you whether or not the link deserves to be there. Put yourself in the users shoes – if there’s no logical reason you’d want to click on the outbound links, then chances are, the site’s selling links.
Image credit Tim Parkinson
