This link is valid.
about the first vid, is he on a zx10 cause my 600 cant not power up like that by just rolling on
His bike may be lower geared, perhaps; but honestly I believe from personal experience that if your sitting just right and have proper throttle control with correct body input, you can throttle anything up that has moderate power, down to an XR50.
Once you know how to get it up well, you can drop your rear sprocket's teeth to where you cant power up so much but you have longer wider gears. So you feather the clutch and slip it up; finding yourself with a more useable gear for maintaining the wheelie.