IllegalBillboards.org and its sister site IllegalSigns.ca consist of "volunteers working to identify and remove illegal billboards and signs,â€ in cities such as New York City and Toronto. The organization uses internet tools such as Google Earth and historical photography to seek out unlawful signage and have the nasty offenders removed.
Permit-less or improper sized billboards are being put up in illegal locations because the legal spots are all taken, adding ugliness to the cityscape. Rami Tabello, of IllegalSigns.ca, estimates half of the billboards in Toronto are illegal. The Anti-Advertising Agency encourages others to get out and help the cause, and provides detailed instructions of the proper process on their website.
The images here are from an IllegalSign.ca slide presentation.