Web Applications Scalability

Please do take care of the scalability concerns of your application or at least architect it such that it can be scalable later on.

If we ignore this fact at the very start concentrating more on the business aspects of the application (something which is misunderstood in Agile) we are doomed to fail even at the slightest hint of making the application scalable. Do not get me wrong, there are measures which can be taken a little later in the development cycle which can improve the scalability of the application but then they have their limitations. For example something like what to choose as data storage is something you need to decide upfront. Agreed having designed the application with a layer of data access objects abstracts the rest of the application from the data storage dependency but then why do the rework of rewriting the data access implementation. I am very sure we cannot regard such a change as trivial.

Have a strategy to allow the application to scale from the very start will definitely help and it is more a matter of choosing the right technologies and right architecture to accomplish it upfront.