Off Broadway nonprofit Playwrights Horizons will be the first New York stage company to try out AVTiki, a channel for online ticket sales that lets buyers purchase ducats without leaving Facebook.It’s an experiment likely to hold a lot of interest for Gotham legiters, since word-of-mouth is generally acknowledged as the most important factor in influencing ticket purchases — and these days, a lot of such word-of-mouth recommendations have migrated to social media platforms. AVTiki, the brainchild of Canuck firm AudienceView, aims to sand down some of the friction between hearing about a show on social media and buying a ticket for it. So far the only ticketing service that’s fully integrated into Facebook, AVTiki also allows a buyer to reserve adjacent seats for purchase by friends. The service designates the seat locations of those ducats, but actual theater maps aren’t yet available via the channel. The first theater company to give AVTiki a try was Toronto producer and presenter Mirvish Prods., which initiated ticket sales through the platform in the fall. Playwrights Horizons had already been working with AudienceView as part of its activities with sales portal Ticket Central, which uses AudienceView tech to power its ticketing operations. The Off Broadway troupe will launch its AVTiki ticketing with deals on upcoming show “The Flick,” the new Annie Baker (“Circle Mirror Transformation”) play helmed by Sam Gold.