When it comes to link buying, link creation, and link curation Google’s team of experts have in different ways said that just about every okay good way of building links is actually bad and could get your site banned from the Google search engine.
What it boils down to is that the Google search algorithm is based on natural links appearing on peoples websites that point back to yours from a purely natural origination.
This means that any tiny influence on your part will be seen by Google as you trying to manipulate their search algorithm. It’s hard to imagine how a computer driven search engine can possibly make 100 % correct assumptions about what is and isn’t a manipulative attempt at gaming their search engine.
I can imagine them doing a fairly good job and filtering out some obvious greedy attempts by website admins to build backlinks to their websites but then you wonder how they detect possible competitor fraud.
A competing website could build some pretty bad links back to the competing website using forum profiles and comment link spam and possibly get their competitor in trouble.
Looking at some of my competitors I can see that all of the top 3 positions have been filled up by competing sites doing obvious link building techniques that Google would absolutely not approve of.
A competing site admin could simply build some links to these sites that come from forum profiles and this would likely gain the attention of the Google web spam team to take action.
In reality all of this stuff has driven many web admins crazy as to all the changes Google is making to their algorithm as well as worries about competitors doing terrible things to destroy their search rankings.
In reality however if you work on building 30 super high quality links or less to your website it is very easy to attain top positions in Google for even some extremely competitive search terms.
My recommendations are to shoot for links that never use the same key term twice, it would be nice if the links were to different pages of your site and not all to the front page of your website. Most importantly the links would have the biggest impact if they were on sites with relevant subject matter to that of your own.