while its true that the base functionality itself is extremely easy to implement with any CRUD framework (spring/django/RoR/phoenix/whatever), the created app w

while its true that the base functionality itself is extremely easy to implement with any CRUD framework (spring/django/RoR/phoenix/whatever), the created app would not be able to scale to the degree twitter has been scaled at this point. vertical scaling only works to a degree, and horizontal scaling while keeping the data as close to real-time as possible is nontrivial.