Infectious Goodness Standing before a giant red mailbox, London postal worker Imtiyaz Chawan holds the Guinness World Records certificate. The Royal Mail Group’s Payroll Giving Scheme incorporated a record-breaking 975 registered charities and causes (Guinness Book of World Records News, 2012, February 6). Charitable giving is the type of positive behavior that can spread through social networks. Many charities are now using social media for fundraising purposes.

David Parry/PA Wire