What is the difference in Google's treatment of 'nofollow' links within user-generated content compared to sitewide 'nofollow' links?

Google treats 'nofollow' links within user-generated content (UGC) and sitewide 'nofollow' links differently, primarily concerning how they impact a website's reputation and its ability to pass PageRank. A 'nofollow' link is an HTML attribute (rel='nofollow') that instructs search engines not to pass link equity (PageRank) to the linked page. For UGC, such as comments, forum posts, or guest blog posts, 'nofollow' links are typically used to prevent spam and discourage abuse. Website owners imp....