I was searching for an answer I posted, using Google. I knew I mentioned "beltway," "homometric," and "Skiena." But none of the Google searches site:mathoverflow.net beltway, site:mathoverflow.net homometric, and site:mathoverflow.net Skiena hit that answer.

Is it possible that answers, or maybe accepted answers, are for some reason not indexed for Google searches?

  • $\begingroup$ Maybe someone is suppressing you? I just searched using Microsoft Bing for the three words you gave, and Bing also didn't turn up any links to your answer. $\endgroup$ Jul 9, 2013 at 11:52
  • $\begingroup$ I did the three searches using DuckDuckGo and none listed your answer. $\endgroup$
    – JRN
    Jul 9, 2013 at 13:28
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    $\begingroup$ Searching from the built-in Stack Exchange feature finds the answer with any one of the terms, and exactly that answer with all three. If the old MO help guidelines are still around somewhere, maybe they should be edited to say that Google is no longer the best option. $\endgroup$ Jul 10, 2013 at 23:08

1 Answer 1


I think I see why.

enter image description here

Note that the Google Link for the "Difference Sets" question showed that it was "edited 8 mins ago, asked 14 mins ago". This means that the last time Google crawled that question was in the 90 minute period between when the question was posed and when you provided an answer.

In other words, Google didn't know you posted an answer, and so of course couldn't find it.

  • $\begingroup$ Fascinating, Willie! But note that I posted my answer 9 days ago, so its content should have been indexed long ago. Perhaps the recent editing removed the indexing... In any case, thanks for investigating! $\endgroup$ Jul 9, 2013 at 12:15
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    $\begingroup$ @JosephO'Rourke Age is not the most absolute indicator of when Google crawls. They claim to have some fairly complex formula at work determining how frequently to discover new pages on a website and how frequently to revisit previously-seen pages on a website. Presumably their re-indexing frequency is partially based on the frequency of edits to MO pages. But for the content to be 8 days off does seem quite shocking in this day and age. $\endgroup$ Jul 9, 2013 at 12:58
  • $\begingroup$ In addition, StackExchange seems to have tried limiting the crawl rates from search engines on their sites. $\endgroup$ Jul 9, 2013 at 13:01

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