Africa has the fastest-growing cell phone market in the world. We want you to tell us why. How has your mobile changed your life?
In South Africa, mobiles outnumber fixed lines by eight to one. Kenyans own more than 15 million handsets, while in Nigeria, the cell phone has "leapfrogged" the PC as the easiest way to surf the net.
SMS texts have been used to send malaria warnings, raise awareness of HIV/Aids, and even to report post election violence. In rural communities, cell phones are a lifeline for traders and farmers, helping them get better prices and save on huge journeys.
To coincide with this week's Mobile World Congress, the largest event of its kind, we want you to tell us about your mobile.
Why is your phone important to you? What do you use it for? And what would life be like without it? Send us your stories - and a picture of you, with your phone.
Send your comments using the form below. Email your pictures to email@example.com, text them to +44 7725 100 100, or you can upload your pictures here.
The BBC may edit your comments and not all emails will be published. Your comments may be published on any BBC media worldwide.