This is amazing! I have always been baffled by the ever more convoluted parking signs. This is especially useful since very often you have to figure out if you can park while driving by, so you don't have much time to analyse the signs.
It is a great success story but it is also a story of someone being in the right place at the right time. Instapaper was in the app store the very next day after store went alive. Seems like a typical story described in Malcolm Gladwell's book Outliers: