To sign up, simply head over to the "Phone and SMS" settings page in Gmail, add your mobile number and complete a verification process.

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If someone calls you on your mobile number while you're on a Skype call, you can now put the Skype call on hold and switch between the calls.

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You enter your mobile number, a PIN number will be sent via text to your phone, and you then enter the pin on the Web site to see confirmation of all donations you have made via that phone number.

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And at the heart of it is a powerful idea - that your mobile phone number can become the key to your bank account without you having to hand over your banking details to anyone who wants to pay you.

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Free calls and texts over WiFi using your home number via the Xfinify Connect Mobile app.

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Already you can load a number of mobile payment apps onto your iPhone including Square and PayPal.

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