Hat Tip
It's nothing new, but the hat tip is still relevant. We don't see it as often because we don't wear hats like our parent's or grandparent's generation. That said, we can still do it.

That is, we can still show appreciation for some bit of wisdom passed along to us. We can still show our regard or respect for someone passing by or just across the room. There are certainly modern gestures that would allow us to do these things.

Maybe, it's simply tagging someone in a social media post to give them credit for an idea or acknowledge them as a source of information. 

It could be mentioning them in a meeting as someone who while not present still made a contribution.

Excuse us for saying it, but we all benefit from the respect we show others.