Consider that I am working for a company which is selling a software and not publically disclosing most of their customers. I am, of course, under NDA. If I were to apply/interview to/with a different Software giant, which is using our product, it'd be a lovely topic to talk about. However, considering the nature of our software and the size of the giant, I deem it very unlikely that the people I would have contact with would even know about our product, and even less so that their company is using it.
Since I am under NDA, I suspect that, even though Company Bar is using our Software, I'm not allowed to talk about it, correct?