Canada’s Choir! Choir! Choir!–C!C!C! for short–got started as a group of people who met after hours to sing popular songs at a real estate office in central Toronto. They were unusual from the beginning, performing the likes of Toto’s “Africa” rather than the classical compositions chosen by most amateur community choirs and church groups. And then they took off, becoming a large, unique phenomenon that tells us something about music in the present day. Now C!C!C! performs from Carnegie Hall to Brazil. They come to the Ark on May 21.

The intervening steps tell an interesting story. The first break was an invitation to sing at an Art Gallery of Ontario party where Patti Smith was also performing. Fascinated, Smith invited the singers to appear with her. Then, when David Bowie died last year, founders Nobu Adilman and Daveed Goldman brought 500 singers to the gallery for a performance of “Space Oddity.” A video of that performance went viral, thanks to social media postings by, among others, Twitter founder Jack Dorsey.

“Something has really clicked about how [Adilman and Goldman] seek to connect groups of people who just want to sing out loud without judgement,” noted blogTO.com. The David Bowie tribute led to an appearance at Toronto’s Massey Hall, where Choir! Choir! Choir! sang “When Doves Cry” in Prince’s memory. Rufus Wainwright led a group of 1,500 C!C!C! singers in Leonard Cohen’s “Hallelujah” last June at Toronto’s Luminato Festival, before Cohen’s towering final album hit the streets.

Now C!C!C! is a protean entity that can break off into groups of various sizes for festival and club appearances, for conferences, and even for corporate team-building exercises. C!C!C! still meets weekly at a Toronto bar to rehearse the founders’ arrangements, which are simple enough for ordinary singers to learn by ear (participants sometimes carry cues on sheets of paper). The group is an organic happening that’s gone viral, a musical analogue for the online sphere in which everything is simultaneously personal and global. A Choir! Choir! Choir! show is, as the Toronto Globe & Mail put it, “both a live concert and a social experiment, blurring the line between audience and performer.” The group is something new in the world of folk music, which, among other things, has always been a template for the efforts of ordinary individuals to make personal the music given to them by large institutions.