[...] how important it is to share our appreciation for others while they are still alive to hear it.
#33,703In this context, Copyright is correct; the meaning is "with it" or "in the know."
There are helpful online reference for American English usages that don't necessarily appear in older dictionaries; look for "slang dictionary" in search engines.
Parla, Sep 23, 2010
"So you like this place? Anything in particular?"
"Well, I was floored by the professionalism of the people."
Parla, May 26, 2016