I work at a coffeeshop. It's a chain. I was working the other day and a girl I used to work with at another location came in for coffee. It was kind of busy so we didn't have much time to talk. When she got to the counter I greeted her and she said "You used to work at" and I interupted and named the location we both used to work at and said "I thought that was you, what are you up to these days?". She told me she was working on finishing school and working at a restaurant that just happens to be a few blocks from where I live. I said "I haven't been there since they changed locations".

She said it was still good. I mentioned checking it out sometime and she said "They have a great happy hour from 3-7, you should definately come by and check it out sometime". The people behind her in line were starting to look pissed, so I took her drink order and told her I would stop by. My question is, was this an IOI or simply her being polite?

Hmmm...I don't think it's necessarily an IOI, but it's still good.

If you saw an ex-coworker and you were repulsed, turned off, or simply not in any way interested, would you invite her to the restaurant where YOU worked?

I'd say that the girl has at least a mild interest in you as a person. She sees you as someone cool enough to pop in and visit her at work. She's not going to invite some geek to her work who could come there and possibly embarass her.

I wouldn't go to her restaurant though. Wait for her to come back to your coffee shop or "run into her" near her work and tell her you'd like to come to the restaurant, but only if she is working or comes with you. Then tell her you'll need her number to find out what dates will work for the two of you. Then, don't go to her work ever - make totally different plans. The other AMOG guys who work with her, may try to run tests and shit-talk you if they are also intereseted in her, plus her female co-workers will also have to "approve" of you. I'd suggest going somewhere else, definitely NOT where she works.

But, to answer the question in your post:

It is definitely pleasant conversation and that in itself COULD be an IOI, but not for SURE. I'd say try to set up a second conversation where you aren't working and take it from there....

I don't want to be the one spoiling your fantasies but if I am correct than a PUA should consider this as an IOI and react on this. The one thing I definitely remember from everything I read from the PUA community is that you should consider even the smallest tiny thing as an IOI and try to get the girl. If you were wrong, no problem, betterluck next time.

Hard to really tell from what she said, her body language would have been ur best bet. Were there any accompanying iois? did she play with her hair, or smile alot, her eyes wulda told ya alot too. Worst case, She works at a bar, so go to happy hour, sit at the bar n get chattin wit her, if ur not gettin the vibe, i bet ull still get some free drinks out of it.

Don't believe that every facial expression is an IOI or IOD. She invited you to something, she wants to meet up again, even if she's being polite/friendly that's an IOI in my book. Gives you the opportunity to see her again. Now, how you want to play it is up to you. I wouldn't recommend going alone. Looks desperate, head there with a friend or two like you're going there for a good time not to just meet her.