A link marked with
rel="ugc", introduced by Google in September 2019 to identify links inside user-generated content (forum posts, comments, profile fields). Sits alongside rel="sponsored" and rel="nofollow". Google treats it as a hint about how to attribute and weight the link, rather than a strict directive — meaning a UGC link can still pass some signal if the surrounding content is high-quality. Most CMS comment plugins now apply rel="ugc nofollow" automatically. Search engines other than Google have varying levels of support.