Update eip-721.md

Author: fulldecent

EIPS/eip-721.md

@@ -368,6 +368,11 @@ Test cases for an implementation are mandatory for EIPs that are affecting conse
 
 ## Implementations
 
+[Su Squares](https://tenthousandsu.com/) an advertising platform where you can rent space and place images
+
+- Bug bounty program https://github.com/fulldecent/su-squares-bounty
+- Implements the complete standard and all optional interfaces
+
 ERC721ExampleDeed, by Nastassia Sachs: https://github.com/nastassiasachs/ERC721ExampleDeed
 
 - Implements using the Open Zeppelin project format