Relay is worked on full-time by Facebook's product infrastructure engineering teams. They're often around and available for questions.
Many members of the community use Stack Overflow to ask questions. Read through the existing questions tagged with #relayjs or ask your own!
Many developers and users idle on Discord in #relay on Reactiflux. Get your invite here!
#relayjs hash tag on Twitter is used to keep up with the latest Relay news.