Google announced the link spam update on 26th Jul 2021 in a Search Central post titled "A reminder on qualifying links and our link spam update".
The change would make Google "even more effective at identifying and nullifying link spam more broadly, across multiple languages". The rollout was expected to run across the following two weeks, per Search Engine Land's coverage.
The post doubled as a compliance reminder for the link types in scope: affiliate links, sponsored posts and guest posts. Those should carry the appropriate rel="sponsored" or rel="nofollow" qualifiers.
"Nullifying" is the operative word.
Google ignores or discounts spammy links rather than issuing a penalty, the approach it has taken since Penguin 4.0.
Sites whose rankings leaned on such links could still see drops that feel like penalties once those links stop counting.
Google's spam help pages note that a ranking boost lost this way is not something a cleanup brings back.
Google announced a two-week rollout. But its ranking updates history logs the July 2021 link spam update at 29 days.
That puts completion at 24th Aug 2021, roughly twice the announced window.
If links are why a site moved, the fix is the reminder itself. Qualify paid, affiliate and guest-post links correctly.
Review the link spam section of Google's spam policies.
