Cho and I got into a VERY HEATED DISCUSSION over whether one checks in “to” or “at” a location with Foursquare. I insisted on “at.’ Cho vociferously disagreed and called me old. Now my feelings are hurt and I still don’t know which is correct.

By the way, Cho would badly like you to go here…
(alexbalk)

You’re being bewitched by language! You can be “in a place,” sure. But where do you check in? HERE. And how do you describe here? It’s the place you’re at.

So there’s an easy transformation of language principle-type thing: Let’s go there. We’re here. We’ve checked in here. Where did we check in? We checked in at this place.