The crucial difference here is between using a totally open-sourced technology like Storm (or Heron, if they release it) and being a consumer of a public API wi

The crucial difference here is between using a totally open-sourced technology like Storm (or Heron, if they release it) and being a consumer of a public API with a proprietary implementation, or making use of their platform/users/data. Twitter can absolutely block you from their API. Or come out with a competing product that integrates with their own systems better than your product does. But if you're using Storm (or Scalding or whatever), there's really nothing they can do to screw with that.