So I talked to the guy for a little more than an hour, and... it... wasn't a disaster :)  I mean, I'm only really gauging it against the other first-time conversations I've had via IM, which were almost universally painfully awkward, and this one was not bad at all.  When I felt like we were running out of steam on one topic, I segued to another, I asked him questions, I complimented his photography... it was pretty good :)

Now, here's the one sort of dark spot - I can never quite tell how the other person felt about out conversation; like, do I consider this a success only because it wasn't a disaster, lol?  So I figure next time he's on, I'll wait and see if he IMs me... and if he does, then I can only assume that he liked me well enough t want to talk to me again... and then we can take it from there :)