Very interesting and very odd. I'm sitting here writing my last paper of the semester and I get an IM.
The conversation goes as follows:

CuddlingCoho: Hey.
GrendelT: hi, who's this?
CuddlingCoho: I should ask the same. you started the conversation
GrendelT: did i? when?
CuddlingCoho: [12:56:07 AM] InstructiveCoho: Hey.
GrendelT: (11:55:59 PM) CuddlingCoho: Hey.
GrendelT: so, apparently you're on the East Coast...
CuddlingCoho: yeah... so do I show up as "CuddlingCoho"?
GrendelT yeah, and I guess I'm "Instructive"
CuddlingCoho: you show up as "InstructiveCoho"
...

From there we exchanged actual screennames. I had assumed we were somehow going through some sort of IM proxy, hence the altered screennames at the recipient's end. A little bit of Googling for "Coho" returned this tidbit of information about TheGreatHatsby.

Apparently this little game has been running around on the net for quite some time, coming and going as interests change. After speaking with "axelstudios", aka CuddlingCoho, we discovered we had both just "dugg" a story on Digg. I'm guessing this phishing bot crawls Digg's live activity page to find users that are currently on, goes to their user profile page and screenscrapes their IM screenname. The trap is set and one IM between two random strangers fires off the lulz.
Quite brilliant in my opinion. I'd like to run it for a little bit just to read some of the IM conversation logs.