So Christopher did an experiment: he posted this message on Twitter:
We love this little canvas drawing program because it makes us feel like five year olds: http://colorillo.com/aazr?tnehlj
He posted this to a (quasi?) official Twitter account of Mozilla, called @mozhacks which has more than 2500 followers. What happened was a storm of people rushed to Colorillo and started drawing. Luckily the server quite stood up to the demand.
I am really glad that Christopher did something more: he recorded a screen video of people going crazy! It is so fun to watch! Here it is (I mirrored it on this server, I hope this is ok for Christopher):
After all, thanks Christopher for testing out my server. I really like the outcome.