Meaning Off topic
Type Acronym
Rank ★ ★ ★  Common
Usage Online Only (chat, messaging, e-mail)
Comments For example, "OT: (some unrelated statement)." Often used in online discussion boards when posting a message that does not relate specifically to the current thread.
Example "This is a little OT, but has anyone noticed more bugs in the latest release of the program?"
Updated October 5, 2016
Meaning Other topic
Type Acronym
Rank ★ ★ ☆  Average
Usage Online Only (chat, messaging, e-mail)
Comments Refers to another subject. Not as common of a meaning as "Off topic."
Updated September 11, 2013
Meaning Overtime
Type Abbreviation
Rank ★ ★ ☆  Average
Usage General (not just online)
Comments An abbreviation commonly used in sports to refer to extended play if the score is still tied at the end of regulation time.
Updated October 1, 2014