Every week there are more and more people receiving penalties from Google for unnatural links, and often these site owners were not aware that the links they were paying someone to build on their behalf were not acceptable in Google’s eyes.
Unnatural links is:
The most obvious paid links will use commercial anchor text
They will often be listed on pages under our sponsors/donors/advertisers
They are quite often site-wide with links in the sidebar or footer
Unnatural link is not beneficial for website. it create spam. Unnatural link not helping in drawn the visitors to site avoid the unnatural link from site.
Any link that is created with the intention of improving your site’s ranking in the Google search engine results in considered unnatural to Google. To understand why this is the case, let’s look at why links are important in the first place.
If you see this message on the Manual Actions page, it means that Google has detected a pattern of unnatural artificial, deceptive, or manipulative outbound links. Buying links or participating in link schemes in order to manipulate PageRank is a violation of Google's Webmaster Guidelines.