The Idea of Public Forum

Wherever the title of streets and parks may rest, they have immemorially been heldin trust for the use of the public and time out of mind, have been used for the purposes of assembly, communicating thought between citizens, and discussing public questions. Such use of the streets and public places has, from anceint times, been a part of the privileges, immunities, rights and liberties of citizens.

Hague v. CIO, 307 US 496 (1939)

Sidewalks in Cyberspace PDF