John Mueller from Google said at the 14:08 mark in the webmaster hangout video from Friday that Google doesn't perform "Spring Cleaning" on their search index. He said "it's not that we have Spring Cleaning in our index," when he was asked about a site losing pages in the Google index.
Here is the video embed at the right time:
We work on a huge website, justanswer.com and since late April, early May, we have experienced a big drop in pages indexed. This happened across all our international sites. We werenât changing anything significant in the last couple of months. What could that be? Or is this just a regular index clean up that Google does every Spring?
So from our point of view, itâs not that we have Spring Cleaning in our index. We try to recrawl and reindex essentially URLs like normal.
I took a quick look at the web site to kind of see what type of site it is and it looks like it is heavily based on user generated content. So this seems like one of those sites where from our point of view, our algorithms might go and say well there is lots of low quality user generated content here, we have to be carefulâ¦
The answer goes into low quality user generated content and how that can hurt a site, which we've covered before.
Forum discussion at Twitter.