[wisty]

So Heroku is good for higher margin sites. You couldn't run Facebook, because the value of each customer is marginal, and they are expensive customers.

You could host a B2B app no problem, because they are paying (high margin) customers, and will probably not use too many resources.

[dasil003]

No platform could run Facebook. There is a certain scale where you have to do it yourself because no one else has done it that way before.