Google's Distinguished Engineer Matt Cutts has responded on Twitter confirming what is believed about the purpose of the Penguin update – work against unnatural links. Matt said, "Links are a Primary Area to Monitor" on Twitter and this has substantiated the SEOs belief that the Penguin is a link based algorithm.
However, the use of the word 'primary' in his response on Twitter has not gone unnoticed and people are wondering what other factors the algorithm could be changed to. This Tweet by Matt came in response to a query on fixing the site against the Penguin. This concern from webmasters about the Penguin has sprung up following Matt’s advice on SES SF where he forewarned publishers against Penguin jolts.The Penguin Update is 'Primarily' About Links - Matt Cutts!,