The question doesn't hinge on you understanding the difference between a technology and a concept. The question hinges on two things:
- is there anything going on in this industry that you think is worth "following" - whatever following might mean
- how clearly, accurately, and passionately do you talk about whatever that is
It might be concurrency and parallel programming. It might be GPGPU programming. It might be programming for handheld devices. It might be moving everything to the cloud. It might be some new programming language and framework or platform you've been playing with in your free time. Once upon a time you might have been able to answer this with something about Agile, or Ruby on Rails, or web services. The key is that you don't give a one word or one sentence answer.
I mean come on! You want to work in this industry, right? Why? The answer to this question should burst out of you.
"X! Because X changes
EVERYTHING and it's SO COOL and I remember when I first saw it I knew
it would be great [or I didn't realize what it was] and then I started
doing some of it myself [at home or after hours or on my second
assignment] and wow oh wow I could see that [cool stuff about X] and
now I read blogs about it, I follow [a,b and c] on Twitter, I went to
all the X talks at [CodeCamp or whatever] and I just think it's the
Seriously, they offer you a chance to go all fanboy (or fangirl as appropriate) on the tech of your choice, and your response is "What? programming concepts aren't something you can follow! This question is ill formed." Don't do that. The interviewer is throwing you a giant softball. Hit it out of the park.