In short that is who you write your content for. Think about that for a second and let it sink in. What does that mean? So, if your a local dentist or you have a local dentist as a client and you want to use white hat only methods (and this applies to pretty much any niche) you need to get backlinks from dental related sites. So who are you writing your content for? If you write for the potential customers, the content if its awesome will get some FB shares and a Tweet or two and if your really luck a Google plus 1! If you want to attract backlinks form related site you need to write content for related sites. This vertical, non competing sites same niche, same market, same industry, same location etc and find some angles. The possibilities are endless. Are you getting me at all? Do you understand what Im saying? So here is an example idea, if you have a local dentist you need to rank, get an awesome article written on the best Enamel used and the different enamel companies you have seen to be the strongest, and then you can talk about a dental lab that does the BEST work in london that applies the enamel and turns it into a perfect high quality crown etc etc. And there you can attract some HIGHLY relevant and powerful niche related backlinks, get in touch email them, let them know before, during and after for example.