Wherever people meet.
A week before
Before
See who's going and who you might want to meet, and why. Pick the people you'd like to meet. They only find out if they pick you too.
On the night
In the room
Scan someone's badge, or type their number, and you're connected. Jot a note only you can read. The people who fit what you're looking for show first.
8am the next day
The morning after
Everyone you met, with your notes. Call them, email them, or propose a catch-up.