I don't think Twitter would have existed, if they had had to take the "grow"/plan for scale path. As I understand, Twitter originally was little tool, that the

I don't think Twitter would have existed, if they had had to take the "grow"/plan for scale path. As I understand, Twitter originally was little tool, that the founder just wanted to have for them selves. If they had thought, they would have to take months to implement it in a scalable version right away, they might not have done it. I also think it's a good idea to throw a bunch of small, simple stuff on the wall and see what sticks. If everything is planned to be a big engineering effort, made to scale to millions of users, you spend a lot of time building stuff nobody will care about. That's why frameworks like Rails are great. They probably aren't perfect for your use case, esp. once you want to start scaling to crazy user numbers (although high user number will probably work very well), but they help you get a useable version out of the door crazy fast, compared to an all custom implementation.