Good afternoon,

Links don’t just improve your profile in the search engines; they also provide another way for people searching other sites to find you, thus increasing referring traffic.

The strength of links is determined by the weighting or authority of the site linking back, so it’s not simply a question of being ‘the more the
merrier’. Certain links, for example those from local authorities or the big nationals are worth their weight in gold.

Going back to relevancy, this is certianly a factor to bear in mind. If you obtain links from authority sites within your industry, the link will provide a great deal od benefit in helping you increase your own rankings, provided the correct anchor text is used to link to your site.

If your site is of value and contains good content however people will link to it naturally, as this acts as link bait. Potentially consider a business blog, as the search engines love blogs due to the regular content updates.

I hope this helps.

Rob Arkell

http://www.impactmedia.co.uk/

There is some discussion as to how much relevancy actually matters, Matt Cutts Head of Anti Spam at Google says that it does but its difficult to know for sure.  Best advice is to follow what David and Rob have outlined above.   

Leaving the hundreds of links spam to one side the discussions I have seen concern a situation where (in theory with all other things being equal), Link A (from a site that is relevant) is the same value as Link B (from a site which is not).

My feeling is that this is possibly the case at present but may not ultimately be true moving forward.

Would never go for link Spam full stop and would (as perviously stated) follow the above advice at least in the first instance.

Also important to note that not all links from irellevant sites are spam.

You will hear all sorts. But if you wish to be super sceptical then I would always try and get some links from themed sites. The reason being that whilst there may be no overriding evidence/proof that theming of links takes place Google have the habit of introducing new algo factors when they see fit.

There are many patents and things that google have looked into (for example and old one is "Hilltop") that tell you where they may be heading.

So to future proof yourself think about what they might do next. Relying on one type of link or SEO method is foolish, as when it all changes you have to play catchup. When the masses start doing it then you need to be wary of getting caught up with the crowd.

So in summary, try harder to get some themed link.

Can I suggest looking at Ken McGaffin's article on the link building mindset.

He outlines 13 principles of link building, based around the idea that a small number of links from authority sites can be so-o much more valuable than a large number of links from sites that have very little authority.

Hope that's useful. 

Justin