Many, many moons ago (like literally thousands of sleeps) it used to be an occasional practice to convey some info in a thread title, but then leave the body of the post blank. We had a poster named belinda who was infuriated by this habit and would occasionally chew somebody out when they did it.
Some incorrigible jackass (who shall remain nameless by virtue of the 5th Amendment) thought it would be funny to start putting (belinda) at the end of thread titles when they didn't contain any further discussion, and it sort of caught on.
It's now more of a shout-out to old-school TBD'ers to elicit a nostalgic chuckle.