since rails has so much convention, you can write a system that scales it as long as peopel follow that convention. PHP is a free for all. Different framewor

since rails has so much convention, you can write a system that scales it as long as peopel follow that convention. PHP is a free for all. Different frameworks do things differently and need to be scaled differently. Lots of people don't use frameworks. I think it will be hard to write a "one size fits all" infrastructure solution for PHP, like what Heroku did for Rails.