Even if you despised the first episode of the new ABC Family reality show “The Vineyard,’’ you have to admit that the stars do some good PR. The cast of the Martha’s Vineyard-based series, which premiered Tuesday night, spent much of Wednesday talking to fans on Twitter, pumping them up about the first episode, and flirting with them enough to earn a few “OMG’’s. Jon Franco (inset), described by ABC Family as a pre-med student who is letting loose on the island for the summer, seems to be the fan favorite. Avery Moore tweeted, “Basically when @JonRFranco smiles every girl across America swoons.’’ Rachel Burdios went for it, tweeting, “@JonRFranco omg you’re perfect.’’ Maeghan Christensen went a bit deeper and asked Franco if he was a Bruins fan. He responded, “hugee bruins fan!!’’ She replied, “literally makes you 200x more attractive.’’ (That’s all it takes, apparently.) The stars kept #TheVineyardChat trending on Twitter in Boston for much of the day. Of course, the real test for the show will be ratings, which come out on Thursday.