SAN FRANCISCO , CA (June 1, 2009) ? The Participatory Marketing Network (PMN), an organization that helps marketers transition from push and permission marketing to participatory marketing, today released results of a new study showing that only 22 percent of Generation Y consumers are using Twitter. When asked about social network usage, however, 99 percent of this same group reports having an active profile on at least one social networking site. PMN conducted the study in May 2009 with its research partner, the Lubin School of Business....