Adam Shostack 
When someone [you're talking to] asks you “what’s new” at a conference, the very worst answer is “same old thing.” You have a chance to remind them of who you are, what makes you special, tell a funny story like “I don’t think I’ve seen you since X happened...” Even if you want to say “same old thing,” you can say, ‘It’s amazing, but I’ve been farming cabbage for 16 years now! Whodda thunk?"
The reason non-answers are bad is because the conversational baton was just handed to you, and you're batting it away, rather than taking it. You're making the other person do all the conversational work.
Do you really have nothing you want to talk about? Why are you even at the conference?
Sheldon@adamshostack if someone unexpectedly asks me out of the blue what I've been up to I have 2 reactions.
1) Why'd you have to ask me that? I barely know what day it is today.
2) Where the hell do I start? Does he really want to hear about the colonoscopy I had last month?
Granted it's a conference and if you go to one of those things, you should be prepared to run into someone you know and have some good responses ready to roll.
That said, if you've ever been to a high school reunion you'll know what I mean when I say that the conversations you think you're going to have never end up being the ones you end up having. If you over-prepare, it'll be obvious. Normal conversations never play out the way you foresee.
Semitones@sysop408 @adamshostack I'm guilty of "same old thing" (not at conferences) because I'm usually not prepared for the question. Sometimes saying "same old thing" gives me the time to follow up with something more interesting. "You know, been farming cabbages, etc"
@semitones @sysop408 not at a conference, totally legit. At a thing where you're wanting to network, I encourage everyone to have at least some semblance of a thing you want to talk about.