Building Virtual Communities for Product Testing: Tips Needed

Hey - just watched the podcast with Greg Isenberg and Flo (Lindy founder), has anyone had any experience in building a virtual community / focus group? I want to test some product mockups / prototypes and virtualise it (e.g. match their persona etc) vs traditional route of recruiting that community and outreach research. This was mentioned towards the end of the pod so interested if anyone's seen it be done, or a suggested Lindy flow