Why Nofollow Links Not caused you for Google Penalty

In a latest video by Matt Cutts, the query of how no-follow, outbound links affect long-term Search Engine Results Pages and whether Google has a policy of penalize sites that only link out with nofollow tags. He answers the question undoubtedly enough by saying no, not necessarily. though, reading between the lines, we can see a little twinkle on how Google essentially looks at nofollow links on a site.