The web has become an excellent resource for locating and even learning established mathematics. Finding papers is easy with the ArXiv and MathSciNet, and (even rather technical) definitions can frequently be found on Mathworld and Wikipedia. On the other hand, the web still lacks good tools for exploration and discussion of the mathematical frontier. We hope that the Garden can help fill this void, playing a role complementary to that of these other sites. Thanks to a wonderful community of users, Wikipedia has quickly built an impressive library of established knowledge. We hope that the Garden will help our community to build an equally impressive online mapping of the frontier of our knowledge.