Apps that use the internet app store, cydia, facebook, etc... can appear hung if you pause your cable modem & run a wifi router. I think it's because each http request tries wi-fi, cable modem fails request, and has to switch to 3g. Since the router appears to be functional and the signal is strong I think it has to wait while constantly switching back & forth.

I sometimes pause the cable modem for my Cox connection and I forgot to unpause it. While it was paused it seemed like my iPhone was hanging every other app.

If wi-fi was off this didn't happen. That's my guess.

Just an FYI to save someone else grief.