The other aspect to badges are their usefulness to convention staff. Depending on the conference, you may have 30 different types of badges, and real humans all

The other aspect to badges are their usefulness to convention staff. Depending on the conference, you may have 30 different types of badges, and real humans all around the conference need to interpret these things for sometimes tens of thousands of people. Badges need to be unique, easily differentiated from each other, not easily lost or destroyed, and (ideally) carry uniquely identifying information. They should be hard to duplicate, easy to verify, and include useful information on the back (such as contact information, conference dates/hours, and rules and regulations). They may convey emergency response information, age, a photo ID, and convention access designations. And they have to work within the constraints of convention registration, which includes buying/generating a brand new, personally-identifiable badge on-site. All these considerations typically trump your networking goals. If your convention has a "good networking badge", it may suck for use by the convention staff. (also, a lot of conventions don't learn from others and slowly, painfully evolve their badging. and the people designing these badges often never had to actually use the damn things)