What is the difference between "footbag" and "hacky sack"?

Footbag is the name of the sport about which this entire website is devoted. You can find a quick overview of the sport by looking at the Sport of Footbag page.

"Hacky Sack" is actually a trademark of Wham-O, Inc., which also happens to be the worst footbag manufacturer. Though most people refer to the somewhat casual game of kicking a footbag in a circle as "hacking" or "hacky-sacking", this is a misnomer. Most advanced footbag players call it either "kicking" or "shredding".