Good afternoon Umberto,
I was just flying through O'Hare this Thanksgiving and noticed that United had put up big bright yellow Jet Blast signs at every single gate in Terminal 1 (Or at least every gate I saw). They are a really prominent feature now. Coming back home, I flew American through T3 and they do not have them. However, every single gate at T1 does have them now. I figured you may want to know about this as they were recently added it seems.
Here's a picture: