Since the introduction of Google’s penguin 2.0 algorithm, backlinks have become a far more risky proposition. Where as any backlink used to improve the status of your websites, now just one bad link can damage your page rank, and how Google defines a bad link has become far more wide ranging in the last few years.
There are 2 types of link building in particular, which used to be the easiest way to improve your ranking
which are now the biggest liability threatening your SEO process –
Were once the most popular way for web developers to build a ranking of a page. Now link exchanges are virtually dead with the alterations to Google’s algorithm. If anyone offers you a link trade then you’re best not getting involved.
You should avoid both buying and selling paid links from your site. The way Penguin 2.0 works does not account for old your links are. If there are bad, cheap links, even from a few years ago, then you page rank will suffer.
There are other links as well which can negatively affect your ranking, such as bulk press releases. Due to the poor quality of these press releases, having one backlinked to your website can also now seriously affect your page rank.
So any bulk press releases that you have linked to your website should also be removed as well.
If you are serious about your SEO and page rank then you should remove any paid, or exchange links that you have acquired over the years.