Encoding restaurant reviews in your tips

Ian Hickson’s new blog post demonstrates why he’s a geeks’ geek:

One day I looked at my bank statement and it was something like:

POS Trans ZIBIBBO PALO ALTO CAUS $76.00
POS Trans CHEESECAKE PALO ALTO CAUS $40.00
POS Trans OUTBACK #0514 CUPERTINO CAUS $210.00
POS Trans BROOKFIELD’S REST #2 SACRAMENTO CAUS $34.00

Look at all those zero cents… there are data bits there, lying unused! It struck me that with every single restaurant transaction I could set the cents field to some number under my control, thus allowing me to communicate with myself at a later date!

So he develops a system of annotations about each meal which he tries to insert into the cents value of his credit card charges, by adjusting the tip he writes in. Turns out that no restaurant actually charged him what he wrote…