Google Operating System blog has noticed a flaw in Google search algorithm that is showing spam sites in the top rows of search results.
The GOS post says
If you go to Google's homepage and click on the special logo that celebrates 25 years of TCP/IP and the New Year, you'll be sent to the search results for [January 1 TCP/IP] and you should normally see a Wikipedia page as the top result. But the first page of Google's results has changed dramatically in the past hours and all the results are new: most of them are from spam sites, pages that discuss Google's logo and quote from Wikipedia.
The reason for the flaw is identified as the recently introduced feature of Google search algorithm
that indexes pages faster and show them minutes after they are published that promotes recent pages if certain conditions are met [Thanks Chitu for informing us about the mistake in the post ].