Sean Marotta put on Twitter an open offer to have coffee, thinking that one or two young lawyers in Washington, D.C., might have interest in meeting him, a seventh-year associate in Hogan Lovells’ appellate practice.

But then the requests multiplied. Marotta, whose Twitter presence is among those central to the #AppellateTwitter online community, ultimately met with 15 summer associates this year from a variety of law programs in the nation’s capital. He would greet them in Hogan Lovells’ concourse, walk them over to a nearby Starbucks and then talk for an hour.