While reading Janne's (aka Ecyrd and creator of JSPWiki) blog, I ran across a post titled YAWN with this:

11:49 * DonPark YAWNS. 11:48 * Ecyrd haukottelee

I yawned textually on #joiito IRC channel recently and the yawn spread to not only people on the channel but also to other channels by those logged into multiple channels.  Janne concludes that:

Yawning has amazing power. We truly are social creatures.

Yawn is a special type of meme, a highly infectious notion that evaporates within seconds of infection.  In fact, it is one of very few memes that can infect across species.