This billboard isn't just a gimmick. OK, well, maybe it is. What I mean is that it's not joking; that solar panel is actually functioning and sending juice back to the grid. Not very much juice, mind you, but some juice nonetheless. At night, it powers its own lights, which is a nice touch.
And while yeah, it's nice that this billboard is powering itself, it's not like its cost efficient. That solar panel probably cost so much that this billboard would have to run for at least a decade to pay for itself. But hey, it's nice that they're promoting renewable energy, right? You can't complain about that.