This Instructable shows how to make an Electricity Monitor for your home that utilizes some of the key capabilities of the Arduino Yun that make it an Ideal choice for Cloud Enabled sensor projects such as this.
WiFi connection allows continuous monitoring of Power Consumed
Utilises TEMBOO for Cloud Support with Google APIs
Cloud Support: Writes Power Consumption to a Google Drive Spreadsheet
Graphing, analysis etc.. available via Google Spreadsheet
A nice feature of the project is that the monitoring is flexible and it's completely wireless (except for the Current Transformer of course), allowing continuous monitoring from a PC or phone and permanent storage on the Cloud.