There weren't any content farms in 2000, and SEO wasn't as sophisticated.
Now both are quite pervasive, and having a marked impact on the qualitative assessments of Google search results.
On the quantitative side, Cutts has recently claimed:
... according to the evaluation metrics that we’ve refined over more than a decade, Google’s search quality is better than it has ever been in terms of relevance, freshness and comprehensiveness.
How does the increase in SEO, content farms, and other questionable results (scraped content, etc.) figure into Google's evaluation metrics?
When we evaluate our quality or a new algorithmic change, URLs can be rated as useful, navigational, etc. They can also be rated as spam. Useful/navigational sites URLs have higher scores, while a spam rating subtracts from the score. If an algorithm change tends to rank higher-rated URLs higher, that's good. If spam tends to rise in the rankings, that's bad.
What our metrics tell us is that Google has gotten better in overall search quality in the last few months, despite also seeing an increase in spam. It's safe to say that now we're putting a lot of effort into the spam side of things to get that back down to the levels we want.
Now both are quite pervasive, and having a marked impact on the qualitative assessments of Google search results.
On the quantitative side, Cutts has recently claimed:
... according to the evaluation metrics that we’ve refined over more than a decade, Google’s search quality is better than it has ever been in terms of relevance, freshness and comprehensiveness.
How does the increase in SEO, content farms, and other questionable results (scraped content, etc.) figure into Google's evaluation metrics?