Great website where you enter your iPhone or Android phone's IMEI and find out when your repair and service warranty is due and whether your device is locked on unlocked by the carrier.
Windows 8 also brings a very transparent tool for examining global indices, where you can also optionally keep track of the value of individual shares.
A really useful feature in case you want to receive a warning notification before you use all of the mobile data available according to your mobile provider contract. It's a great way to avoid additional charges.