Link Attributes (Nofollow, Sponsored, UGC)
The HTML link attributes rel="nofollow", rel="sponsored" and rel="ugc" describe the relationship to a linked target and, since Google's 2019/2020 update, replace the blanket nofollow that was previously the only option. rel="sponsored" marks paid links and advertising placements, rel="ugc" identifies user-generated links in comments or forums, and rel="nofollow" remains the general value for all other cases without an editorial endorsement. Google treats all three values as hints rather than as strict directives for crawling and PageRank flow, but still reads them as a quality signal.
In practice
Paid collaborations, advertorials and affiliate links should consistently carry rel="sponsored", because Google explicitly prefers this marking over the generic nofollow. Comment functions, forums and guest books on your own website should add rel="ugc" to automatically generated links, although particularly trustworthy regular users can be linked without the attribute in individual cases. The values can be combined, for example as rel="ugc nofollow", which is already standard in many CMS and forum plugins. Unlike the backlink, which describes an incoming link from someone else's site, and the anchor text, which concerns the link text, these attributes govern the technical qualification of outgoing links from your own website. For Austrian SME websites it is worth reviewing the CMS and blog comments, because missing or incorrectly set rel attributes on paid collaborations can also create a risk under the rules on labelling advertising.