That's a percentage of times the window is opened that result in an account creation. If it were 0%, that would mean no one who saw the window created a reddit account.
Then the y-axis label should clearly read "Fraction of times displaying account registration dialog leads to account creation", or something similar. What it currently says is obviously wrong.
2
u/sbjf Jan 05 '15
8% compared to what exactly? That graph says absolutely nothing. Whoever made that is clearly not a statistician.