Sophia Efthimiatou and Matt Starr are behind Substack's latest IRL events.Courtesy of SubstackAs Substack sets its eyes beyond newsletters, it's looking to IRL experiences.Substack has been hosting jam-packed readings and parties with its newsletter writers.We spoke with Sophia Efthimiatou and Matt Starr, Substack's duo paving the platform's IRL strategy.I'm sitting on a foldable metal chair lined up in a gymnasium, the marching band is blaring, and cheerleaders are being tossed in the air.No, I'm not a high-school pep rally.