Reaction pulls information from JSON feeds, and allows you to interact remotely with your server. By regularly polling for updates and posting notifications to your device, Reaction frees you from regularly checking other (web) applications for information which may require you to take action.
Reaction is perfect for:
(*) Moderating blog comments: new comments automatically post to your device, allowing you to approve or reject their content.
(*) Renewing overdue library books: send yourself reminders that things are due, and automate online renewal on your server.
(*) Having your robot wash the dishes: are you going to finish the last dregs in the coffee pot?
(*) Responding dynamically to regular inquiries: what do you want for dinner tonight?
Although each of these is, in its own way, ridiculous, Reaction will do what you ask of it.
Reaction requires a data source, which it is up to you to implement. Information regarding proper JSON format and interaction is available in-app, in the help documentation.
For more information, visit Reaction's website at http://eightbeers.org/reaction.