[nkrisc]

OK = Acknowledged or agreed. OK? = Request for acknowledgement or agreement.

Anything else is reading too much into it. If I send someone an email explaining something and I get an, "OK" back, then I assume they've read it (or will read it) and I'll hear more from them if they have more to share.

When speaking in person, the "OK" itself almost completely superfluous as it's merely a vehicle for inflection and other social cues which carry the real meaning, as you noted.

> I'll just go with the sentences that attempt to preclude ambiguity.

And that's what I'd do 99% of the time, but I was specifically pointing to discussion around "OK"