Traditional social-­networking sites are great for connecting people with like interests; meetup.com, for example, helps facilitate real-world gatherings arranged by appointed organizers. The next wave of sites might bring people together at a wider array of local events–such as concerts–without the involvement of organizers. Boston-­based HeyLetsGo uses technology developed by computer scientists from MIT’s Media Lab and the Georgia Institute of Technology to scour the Web for listings of local events, which it combines with feeds from ticketing sites and posts by users themselves. Users link their online profiles to event listings, post messages about mutual interests, and, maybe, connect. Judith Donath, director of the sociable-media research group at MIT, says, “People like it, and I think the idea is solid.” The hope, says cofounder Rebecca Xiong, is that with ­HeyLetsGo, “online is not separate from offline.” The site plans rollouts in several U.S. cities this year.