Apart from performance concerns, should web-based applications be built differently according to the number of (concurrent) users? If so, what are the main differences for (say) 4, 40, 400 and 4000 users?
I’m particularly interested in how logging, error handling, design patterns etc. would be be used according to the number of concurrent users.
I am no expert in this..but here is what I think.
Using design patterns extensively, building extensive logging capability etc. may not be very necessary if the application is going to be used by 4 known users – in the sense that every extra unit of effort you put in brings in lesser rewards.
However, if the application is going to be used by more people, you have concerns such as scalability, security etc. Using design patterns etc may make more sense. Of course I am making the assumption that if its just 4 people using an app – it is probably not very mission critical.
So I believe you should start simple, and make changes as needed. However following good design patterns is always good – ideally your design allows you to change parts as needed.