Upon booting this morning my G1 vibrated 2 quick times so I knew something was different. An error dialog indicated that my SIM card was full and that I should delete some SMS messages. Next it presented me with an unthreaded view of SMS messages. Long pressing allowed them to sometimes be deleted individually. Sometimes they would stay anyway. I deleted a few. Eventually I pressed the Menu button and told it to delete all, but that resulted in another error. Was this a fluke? I wouldn't expect the G1 to store text messages on the SIM card. I had 32 MB of free internal memory and over 5 GB on the microSD. Solution? I shut down the G1 and powered it on again and it was back to normal and again shows messages sorted into threads.