Google has recently announced and revised their Webmaster Guidelines.
According to Webmaster Support
"Any links intended to manipulate PageRank or a site's ranking in Google search results may be considered part of a link scheme and a violation of Google’s Webmaster Guidelines."
It
means if you are intentionally trying to raise your websites PageRank
by smartly using tailored anchor texts in the content on article or
content posting websites, blog comments, guest blog posts, press
releases, paid linking schemes etc. then definitely it is going to be
considered violation of Google Webmaster Guidelines and have a negative
impact on your website's position in Google SERPs.