drawball.com is a massive online graffiti board. there is no user account system, but it is possible to get an ipban if you act like a moron. once you bring up the home page and drawball loads, click anywhere on the drawball to zoom in on that area, you must zoom in to 100% to draw. once zoomed in, click the screen and a puzzle will come up, solve it and you will be able to draw. before you draw, please note that your ink is limited, it comes back over a period of time. new users start out with 15% ink. the controls for changing color and brush size are at the bottom right of the screen. the zoom out button is at the bottom left of the screen. at the top left are located the browse history buttons, you must zoom out anywhere above 100% to use them. they allow you to see what has happened before on drawball.
if your work is of good quality, it might get protected, meaning that no one can draw over it. if it is really good, it could be added to the hall of fame. the hall of fame is accessible by clicking the link to it at the top right of the page.
last of all, dont be a jerk, just have fun and dont scribble on peoples work.
yesterday i painted on drawball.com, and came back today to find my work protected!