Someone posted this on the Pokemon Go sub today. Looks like there are already a fair amount of people using it. I dunno about Halifax in particular. It pops up over top of POGO so you don't exit. You can put out a message with your location, or simply look at what everyone within a 15-30km radius is saying.
I'm in Port Hawkesbury and the app told me 'Hey you're the first to use the app in the area' so I guess if that pops up you know no one else is using it yet!