[freefal]

When it came out, PageRank was a really innovative way to order search results that cut through most of the "SEO" at the time, which was webpages doing lots of unsophisticated things to range well for a given topic (e.g., putting that topic in the <title> many times).

[wolpoli]

Yeah. PageRank worked because web site owners were linking to each other as a service to the "Surfers", signaling what they think are high quality sites. There is an incentive to keep sites high quality or it'll risk being delinked.

When people stopped "surfing" and starting "searching", the whole mechanism broke down. Plus Google started using other metrics for ranking sites these days.