Nofollow Links
Links tagged to signal that they should not pass ranking signals to the target page.
Definition
Nofollow links use the rel="nofollow" attribute to indicate that a hyperlink should not transfer ranking signals. Initially a directive, it is now treated as a hint by major search engines. Nofollow is commonly applied to user-generated content, paid links, and untrusted sources. A natural link profile includes a mix of followed and nofollowed links.