Let's talk, for a minute, about favorites. Let's talk, in particular, about the nuanced uses of Twitter's most multifunctional button. People use the star for everything from bookmarking (the save fave) to props-giving (the rave fave) to presence-signaling (the wave fave) to bone-throwing (the favor fave) to chaos-causing (the hate fave, which you could also call the spice-things-up fave, which you could also call the flavor fave).
There are many more uses, too, because the beauty of the fave is its ambiguity. But the most useful of all may be this one: the farewell fave. Which is the fave that signals, subtly, the end of a conversation. Participating in a discussion that you need, for whatever reason, to stop participating in? Fave its last tweet. Find yourself involved in an infinite pun-off? Fave a tweet. Stuck on a Twitter canoe? Fave a tweet. It's an efficient, and polite, way of announcing, "Aaaand … scene."
This is quickly becoming my favorite form of favorite. I don't use it often, but when I do, I am grateful for it. With a single click, I can do something that is actually extremely difficult to do in the digital context: end a conversation. On Twitter, it'd be awkward, and redundant, and a little bit self-aggrandizing, to announce, "Sorry, everyone, I have to go now." But the farewell fave allows me to say that without actually saying it. Friends of mine have expressed the desire for a similar function in email—a button you could click within a message to signal acknowledgment without reply. I'd love that, too. What could be more useful for the harried gmailer than a button that allows you to participate in an email exchange expressly by ending your participation in it? It'd be the best kind of digital high-five: affirmative, and effective.