Lack of Interest - i.e if something isn't funny or interesting. could be lol
for lack of laughter.
Derived from lol
but due to overuse loi is to show when something clearly isn't funny.
Person 1 - lol
check out this link "blah blah blah dot com"
Person 2 - Loi. /Or Lol (lack of laughter)
Person 1 - Haha did you see such and such tonight, PMSL
Person 2 - No n00b LOI!