"Why should we be limited to traditional bells and lights?" ask the makers of MYBELL. Yes, why can't we instead have a bike horn that hollers at 100-plus decibels, "GET OUTTA THE ROAD, YA JACKASS," because isn't that what some inattentive people deserve?
OK, so I can't find anything in MYBELL's promotional material suggesting that cyclists use it to terrorize drivers and pedestrians with withering, self-recorded burns. But c'mon, the way the product's name is formatted in ALL-CAPS? It's basically telling you to fill it up with incendiary messages – perhaps "MOVE IT OR LOSE IT, CHUMP."
As noted by the good folks at Urban Velo, the way this alleged "world's first customizable digital bike horn" works is simple: You plug it into your computer via a USB cord and load it with two personally selected sound files. The first, accessible with one tap of the bell's button, will be a loud, blaring tone for moments of emergency. (The MYBELL team used a locomotive's horn.) The second is activated with two taps and should be milder, to let people know you're trying to pass, for instance, or simply to put a smile on a kid's face by having your bike cluck like a duckling.
Rounding out the package are programmable LEDs that flash in the angry-red sequence of your choosing. I would suggest Morse code for "HEY, I'M RIDIN' HERE!"