Dweet
Dweet (http://dweet.io) is easy to use platform that allows for user messages to be published and subscribed to it was designed for machine-to-machine messaging for IoT. To use Dweet you just choose a unique name, This name is called a "Thing", it is a grouping for all your messages. Specify your "Thing" in the Dweet Notification Target, the Key is an optional configuration value that is only needed if you want to Lock your "Thing" to keep your messages private. Messages will be forwarded in JSON format (See Default Data Fields).
Platform Setup
Just choose a unique my-thing-name for your "Thing" (must not include spaces).
You can view posts to your "Thing" at https://dweet.io/get/dweets/for/my-thing-name
Notifier Setup
Specify the my-thing-name of your "Thing" in the Notification Target field. Provide the Key to your "Thing" if it has been created as private.