... at a conference, it's easy.... you just quickly look at their badge when you hope they're not looking and then pretend you knew their name all along.
But, as Raymond Chen demonstrates there are so many usability problems with conference name badges that it's a miracle anybody gets to meet anybody else.
It's not just conference badges. At my current client, the ID badges are designed to be hung from the neck on a string with a single clip. Surprise, surprise.... half of the people walking around the site are displaying the blank side of their badge. it would be funny if this wasn't a moderately sensitive site :-(