A lot of link building strategies can backfire, causing more damage than doing good. If you want to improve your ranking in the long term, use a holistic SEO strategy, and avoid certain link building tactics. In this post, I’ll discuss some link building DON’Ts: tactics you should most definitely NOT use. Some of these, you probably already know about; I’ll cover those first. Then, let’s move to 5 less well known – but equally important – DON’Ts.
In the old days, link building meant putting links on as many external pages as possible, often by buying or trading links. Since Google Penguin, these tactics have become a risky SEO strategy. If your link building tactics include spamming, your site risks a Google Penalty and could be banned from Google’s results completely. Placing a lot of links may help the ranking of your site for a short while, but probably not in the long run.
Source : Yoast