Can't add into link very important code - rel="nofollow"1
"Nofollow" provides a way for webmasters to tell search engines "Don't follow links on this page" or "Don't follow this specific link."
More info about this feature:
This code using for many must have features and SEO optimization.
FCK Editor have this feature, but ARK editor skipped it - we haven't backward compatiblу after upgrading to ARK Editor.