My informant told me this joke as a piece of humor relating to current events. It references both a Movie (Great Gatsby) which comes out this (May) month, as well as Facebook chat, a currently utilized electronic media.
Informant: (as a prologue) You know Gatsby right?
Informant: All right, well you know that sexual tension you get when you and your crush are “online” on Facebook at the same time, and you just stare at the green light chat button? Suddenly you realize that you know what Gatsby felt like.
This joke relates Fitzgerald’s classic Great Gatsby, by way of its new movie, to generational issues of correspondence. Just as Gatsby looks out longingly at the green lighthouse light which represents his beloved Daisy, so does this joke suggests those of us with Facebook accounts have a similar experience when looking at the green chat buttons with which we can start conversations with others. Perhaps most appropriately in light of its digital themes, my informant first heard this joke on the internet.