Adds a checkbox in the insert/edit link popup for including (or not) `nofollow` attribute in links.
When the search engine spider sees nofollow on the link, it does not follow the link to the new site, not count the link towards itís popularity score in their ranking engine and not include the link text in the relevancy score for those keywords.
Just check the
rel=\"nofollow\" option under the default
open link in a new window/tab option.