Comment by lclarkmichalek

Many are very critical, and many are not proprietary. Databases and web frameworks are two that come to mind immediately, yet people seem to choose those based on the number of blog posts about them. And almost all APIs are vulnerable to reimplementation. With Parse's API, it would theoretically be possible for another project to implement an identical interface to their backend, and allow you to simply change one LoC in your application to change the provider of your BaaS.