Google's Matt Cutts shared an example of Google 2000 vs. Google 2011. The example is aimed at showing those who feel spam is worse at Google than ever before that it is not true.
Matt showed a search result set from a query he did in the year 2000 and compared it to the same search result set from the same query done today. In short, he shows how for that query, Google has improved night and day in terms of search quality and spam prevention.
But it was one example, and SEOs and others want to see more examples. Matt said he did save 40,000+ queries from October 2000 that he can compare but when I wrote about this at Search Engine Land, I asked Google to let us test it.
How? Google enabled a couple years ago a way to search Google's 2001 index. So we asked Google to re-enable that feature so we can test it ourselves. Matt Cutts explained that it is not feasible because it is just too much work. He said in a comment:
I saw the pain it took to revive that code and index data from 10 years ago. It was a real headache for the engineers who did it, so wouldn’t expect us to do it again any time soon.
So some are asking for the 40,000+ queries.
Either way, I think that I personally would prefer the Google engineers to work on spam as opposed to building out a way for us to test if spam is better or worse today.
I would be shocked if anyone felt that Google is worse at spam prevention today than 10 years ago. A year ago, maybe - but not 10 years ago.
Forum discussion at Google Blogoscoped Forums.