Heroku has been hyped up far and wide as being some kind of magical scaling solution. Just give Heroku your app and it will scale infinitely on EC2, right? Wrong. As they've admitted before, they haven't done anything to scale the database. Adding more app servers is trivial by comparison.

This isn't a knock on the Heroku folks; to their credit, they've been open about the DB issue. But you wouldn't see this most basic piece of information in media coverage from TechCrunch and many others. Unfortunately (?) for Heroku, the press has been writing checks in their name that the company can't cash.

Edit: Literally seconds after I made this post, blasdel posted about the same DB issue: http://news.ycombinator.com/item?id=859545