humma
<chat> A filler word used on various "chat" and "talk"
programs when you had nothing to say but felt that it was
important to say something.
The word apparently originated (at least with this definition)
on the MECC Timeshare System (MTS, a now-defunct educational
{time-sharing} system running in Minnesota during the 1970s
and the early 1980s) but was later sighted on early Unix
systems.
[{Jargon File}]
(1999-02-27)