June 12 marks 10 years of online social collaboration through the Meetup network, formed in the aftermath of the September 2001 (9/11) tragedy. Co-founder and CEO Scott Heiferman says, “I was living a couple of miles from the Twin Towers, and was the kind of person who thought local community doesn’t matter much if we’ve got the Internet and TV. The only time I thought about my neighbors was when I hoped they wouldn’t bother me.”

Then, suddenly, people started helping each other and meeting up with each other and the idea for Meetup was born. Each of more than 100,000 Meetup groups starts with people simply saying hello to neighbors. Membership is 10 million and growing.

To join in, visit Meetup.com.