GooglePenalty ActionConfirmed
Paid link PageRank penalties
Google visibly reduced toolbar PageRank for sites judged to be selling links, signalling enforcement against the paid-link market.
What changed
In October 2007 a large number of sites known to sell links saw their publicly displayed toolbar PageRank cut, in some cases by several points. Google representatives confirmed the reductions were deliberate and tied to link selling rather than a data glitch. The action marked the start of sustained public enforcement against paid links, which was later codified in the link spam policies.
Timing
Rollout began 7 October 2007. No completion date was announced. Rankings typically remain unstable for the whole rollout window, so measurements taken inside it are not a reliable read on the outcome.