StumbleUpon + My Immaturity
The above screenshot(click it to zoom), was taken from this share button I'm working on for a client. I was in the middle of adapting StumbleUpon's submission link when I noticed an unfortunate concidence. They have the url encoded where / is represented as %2f, so /article reads %2farticle. Not your top shelf stuff but it caught me off guard and amuses me still.


