Since then, he has also replaced other letters, as shown here:
* K7EP IT CLEAN
* KE1P IT CLEAN
* KEEP IT 1LEAN
* KEEP I8 CLEAN
* KEEP IT CLE0N
* KEEP 0T CLEAN
* KEEP IT C0EAN
* KEEP IT CL3AN
* KEE4 IT CLEAN
Combined, the phrase becomes "0714 08 1030N".
It was believed that he was writing out a date and time. This appears to be 07/14/08 10:30 which was when Microsoft's slot at E3 2008 was. Fans were exited to hear the announcement at E3, but were taken by surprise that there was no announcement. Instead a mysterious page substituting the Bungie.net homepage with a countdown to 7:07:07 AM, July 16th, 2008.