@_ck_ - Well, most of what I read points to 5.3 not being an option to move towards. It's more like PHP 5.0 at the least. Also, the suggestion was brought up by a user to discuss at the meeting, not proposed by the core developers. About the percentage, WordPress phones home to the WordPress API to check for plugin, theme, core upgrades. Part of the information that is sent back is the PHP version the site is running on. So in that case, wouldn't they have the more accurate numbers?