Printing from your phone; might not be a feature you need that much but when you do it promises to be a great time saver.
"With Gmail for mobile and Google Cloud Print — a service that allows printing from any app on any device, OS or browser without the need to install drivers — you can.
To get started, you’ll first need to connect your printer to Google Cloud Print. For now, this step requires a Windows PC but Linux and Mac support are coming soon. Once you’re set up, just go to gmail.com from your iPhone or Android browser and choose “Print” from the dropdown menu in the top right corner. You can also print eligible email attachments (such as .pdf or .doc) by clicking the “Print” link that appears next to them. "