As a follow-up to my post yesterday, about the Google Custom Search Blog being deleted as spam, I contacted Google to see if I could get any further comment from them. Sean Carlson of Google got back to me with the following statement:
Blogger's spam classifier misidentified the Custom Search Blog as spam. If a spammer gets caught by our automated classifier, the blog owner will receive notification of this identification. At the owner's request, the Blogger team will review the blog to verify that the blog in question isn't spam. In this case, the Custom Search Blog bloggers overlooked their notification, and after a period of time passed, the blog was disabled. The content wasn't deleted, but it was removed from the URL.
Even after blogs are disabled as spam, the owner can write in requesting a review for her or his blog to be restored. If the review proves that the owner's content was not in fact spam, the blog will be restored with all content. So, when we saw what happened on Tuesday -- and were well aware that our content wasn't spam -- we restored the official Google Custom Search Blog. The individual who had claimed the URL and published the blog post in reference still has his content; it's just hosted at a new URL.
I was not able to find out why the spam classifier identified the Google Custom Search Blog as spam. My guess is that Google does not want to reveal any details of their spam detection techniques.
The unfortunate lesson here is that mistakes do happen. Quality content does get flagged as spam at times. While I honestly believe that Google strives hard to do a good job of avoiding that problem, and this makes the problem happen less often, you can still get caught in the net.
The hard part of this is that most people who get caught in this net by accident won't have the access and credibility that the Google Custom Search Blog team had to get their issue addressed. There is, as Google has said, an appeal process, but you have to imagine that there are a queue of such things to get reviewed.