Generally a nuisance, these relatives of moshers propel themselves above the crowd at a concert and are essentially passed around from person to person like a joint. When a crowd surfer is coming your way, watch your head, and try your best as to push them somewhere.
My girlfriend recently joined their ranks during the Smashing Pumpkins set at the Summersault 2000 concert in Halifax.

IMHO, crowd surfing should only be undertaken if you feel you're going to pass out and are using it as an escape method.

As Italiano so eloquently put it on the SP message board,

"IT'S A PAIN IN THE ASS TO GET HIT IN THE NECK AND HEAD WHEN YOU'RE TRYING TO LISTEN TO DROWN LIVE FOR THE LAST TIME IN YOUR ENTIRE LIFE."

I couldn't agree more.