What is Ysomfr?
It is an acronym. You Set Off My Funny Receptors. Similar to "lol" or "rofl."
Bob: Two potatoes are in an oven, one says hey, the other says "holy crap it's a talking potato"
Jill: Hahaha. Ysomfr.
See lol, rofl, roflmfao, lawl, lawlercakes, lawlz