Hmm... I've had the same concern myself.
I probably wouldn't bother with it if it was just about a nebulous, unannounced 'next HL game', but the problem for me is that Valve set up some massive expectations with the 3-part episode series and then just stopped communicating with us. It's frustrating and, in my opinion, bad customer service. I am literally dying in anticipation.
I see the "Call for Communication" group as a way of saying "We are really getting desperately impatient, just so you know." I'm sure they do know already, but this only reinforces the message, no? They can just ignore it. It's nowhere near as bad as that stupid campaign to inundate Valve with real crowbars.