To be upset or sad because of something someone said or did on IRC or another Internet medium. On IRC, this often includes demonstratively quitting or parting a channel after getting pwnd, or alternatively flaming the pwner in incoherent and laughable ways. Can be shortened to "perc."
<pansartax> hey check out this kool image i just made in photoshop
<vaskenalle> HAHAHAHAHA that's possibly the ugliest thing i have EVER seen
<kjempetorsk> lol lens flares? lolololol are you serious? HAHAHA
*** pansartax has quit IRC (i h8z u)
<vaskenalle> heh. perc.