Most YouTube videos allow users to leave comments, and these have attracted attention for the negative aspects of both their form and content. In 2006, "Time" praised Web 2.0 for enabling "community and collaboration on a scale never seen before", and added that YouTube "harnesses the stupidity of crowds as well as its wisdom. Some of the comments on YouTube make you weep for the future of humanity just for the spelling alone, never mind the obscenity and the naked hatred". "The Guardian" in 2009 described users' comments on YouTube as: