All my life I’ve waited “in line”. And boy are my legs tired. But seriously folks, do you wait “in line” or “on line”. I know you Brits “queue up”, but that’s another thread. I’m in the southern U.S. and here we wait “in line.” Not sure if it’s a regional difference though.
I’m not talking about the kind of “on line” you need to be to be reading this, by the way. Unless you are reading this on a laptop while you’re waiting in/on line.
In line. I’m a Midwesterner.
“On line” in anything other than a computer sense, strikes me as funny New York talk.
In line. I’ve never heard anyone use on line in that context.
On line is a New Yorkism, along with “waiting on you.” in a non-server sense.
I wait “in line”, or “in the queue”.
Canadians wait in line, but I’ve heard “on line” from (as has been said) New Yorkers.
In line. Never heard anyone use the term “on line” before.
Speaking of “on” - except on the internet I’ve never heard anyone say “on her period”.
Most people I know say they have their period, no on their period.
“On line.” Yup, seems to be a New York thing.
I’ve only heard “on line” from New Yorkers but I hear waiting on you and on her period everywhere. In fact I say them both and I grew up in the southeast with parents from southern California.
If you mean something like “Where have you been?! I’ve been waiting on you for half an hour!” then we say that in New England too, sometimes. Having spent very little time in NY, I’ve never heard anyone say “on line” instead of “in line” though.
In liner here. Midwesterner.
My SO and all of her NYC/Long Island friends say on line. I like to rib 'em for it.
Oh, and I don’t think “waiting on you” is a New Yorkism. I’ve said it before, and I’ve definitely heard it my whole life.
In New York, you wait in a line formation, but the verb to do so is to wait “on line”. It’s more a state of being than an action. As in, “Are you on this line (…or just standing around aimlessly while other people are getting their orders in, you shmuck)?”
Frequently there are multiple lines going on, so changing lines is to “get off” of one line and “get on” another line. It wouldn’t make much sense to say you’ve gotten “out” of one line to get “in” another, as you’re always “in” a line; you’ve just changed the one you’re “on”.
“Waiting on you” is definitely not a (native) New Yorkism, as I never heard it until about 5 years ago around here. It’s definitely caught on though, to my dismay. I think it’s originally a Southern thing.
What’s the alternative to waiting on you? I’ve heard it and said it all my life so I can’t understand why it sounds wrong to you guys.
“Ready to go?”
“Waiting on you”
What else would you say? 
I say “in line”. “on line” is definitely a NYC/NJ thing as can be seen from number 93 here.
I think the alternate is:
“I am standing on line and I am waiting in you.”
I use the opposite however.
“Waiting for you” or, frankly, something else entirely like “ready when you are” or “yes” 
Are you serious?
Waiting FOR you. You wait FOR something/someone. Not on it. If someone were waiting ON me I’d tell him to get the hell off me.
Wha? You’re not ‘on’ a crowd or ‘on’ an audience or ‘on’ any other group of people so being ‘on’ a line of people makes little sense - no matter how many there are. You could, I suppose, be standing on the yellow line in a parking lot or on the line on the road and then you’d be ‘on’ a line but otherwise it’s just a figure of speech.
:dubious: Of course it’s a figure of speach. “Figure of speach” is a figure of speach. What’s wrong with that?
I grew up next door to NYC (till I moved there) and it seems to me I’ve stood in and on lines, both. (I’ve also queued.) I have a sense of a certain subtle difference between in and on but I can’t put my finger on it. On seems less depressing somehow.