This treasure includes an example of sending a Twitter using Arduino Ethernet. Following the orders of it make you possible to follow the example since it has plentiful explanation and source codes.
However, the difference compare to general examples is that it mostly discuss about a specific example of using WiFi Shield.(Of course, it accentuates advantages of 1Sheeld since it is a blog for 1Sheeld)
You can get the source code and more details from below link.