The good, bad and ugly in Social media, by an ad agency exec

GREAT article from Matt Jones, director of strategy and planning at Jack Morton, about how to use social media for marketing purposes.
Matt uses examples of companies (and individuals) who have done Twitter and Facebook successfully and well and others who are not doing that well.
Also good advices to marketers to use social media to change the way they market and not only as additional elements of their marketing mix
@ Ad Age