What do the spinning arrows mean?

[slapple]

I just activated my iPhone 4S on Verizon. I have 4 bars of reception (turned off WiFi for now), and at the top of the phone, in between the "Verizon 3G" and the time, there are 2 arrows spinning in a circle. They've been spinning like that for 10 minutes now. What does that mean? Oh wait, now the 2 arrows finally disappeared. I never saw that on my iPhone 3G...

 

[verwon]

It's syncing!

 

[quietstormSD]

You're no longer locked out of your phone when syncing in iOS 5. You can freely use your phone when syncing

 

[kulimer]

what the person above me said, no more lock out. It's game time.