I don't know about comp.terminals, but the source of the spam in
comp.lang.cobol is the usual suspect (Google Groups). What made this
strange for me is that when I subscribed to .cobol on Eternal September
two weeks ago, the messages were not there - his spam detection had
removed them.
The thread "More Thai spam in comp.lang.cobol" (23 Jan) covers this.
There have been around 100 new spams in that group today.