With the recent news over the last several weeks of a major Google update that supposedly came out December 17th, Matt Cutts has effectively thrown down the Rumor Hammer and denied that this ever happened.
Barry Schwartz stated that many Google search results tracking tools displayed some major changes within Google’s search results. But it seemed that when he checked things out himself within the discussion forums and social spaces, he found that there was actually very little talk about ranking changes at Google.
That was when Matt Cutts denied it on Twitter. He said that they try withholding any major updates right before the holidays.
Even with Cutts’ denial, it seems that there is some disagreement between him and the tracking tools. Who knows exactly what tripped up the tools on the 17th.