I have had two different interviewers, in two different occasions, asking me one similar question.
What is the number of end users of the application that I am currently working on?
I gave a rough figure to which the panel mocked and said it is very small.
In one case, it was ~ 100 to 200. But, that amount of data that was generated was huge and this has to run 24x7, 365 days. It could have been scaled up later but I was not part of it. Till the time I was involved in it, I was part of the coding team.
I do understand that different applications cater to different users and the numbers vary significantly based on the domain and also on the requirement. I could have been rejected based on this alone or many other factors.
I guess their main intention was to see if I can be a part of applications with bigger user counts. However, I do not have experience working on applications with a large number of users.
**My question is, how should I answer questions like this - where my experience doesn't match what they're looking for - in a way that minimizes the negative effect on me?