This is a simple example of how you can use MBED (http://developer.MBED.org) to get a microcontroller talking to the internet.
Donatien talks you through the hardware and software he used to get an RFID tag to trigger a tweet. Of course, this is just one example; what the microcontroller is looking for, and the web service it talks to is pretty flexible, so the basic approach could be used for many internet connected ideas.
All the details are at: https://developer.mbed.org/cookbook/RFID-Tweeter
Check it out and get inventing! For more details and the full code and writeup, see http://developer.MBED.org.
( Video Source : https://www.youtube.com/playlist?list=PLiVCejcvpsetJ1n9nRXzLWvE4dp4RwGOf )
