I found myself asking the same question. Not sure how heroku's system is much different. Running a web application is running a web application, right? Saying you need "push" is a lousy excuse IMO. Its a "the backend is the backend, right?" question?
Unless I'm missing something, offering sinatra or something lighter would make sense... but it still seems like PaaS to me.
Unless I'm missing something, offering sinatra or something lighter would make sense... but it still seems like PaaS to me.