Resources for Follow-Up
Here are some items from the CSUMB Library databases that emerged when I searched "academic twitter free speech" (no quotes):
Koh, Y. , & Albergotti, R. (2014). Twitter faces free-speech dilemma. The Wall Street Journal Eastern Edition, 0(0)
Schmidt, P. , & Schmidt, . (2015). Campaigns against microaggressions prompt free-speech concerns. The Chronicle of Higher Education, 61(41), A8.
Kopytoff, V. (2011). Sites like twitter absent from free speech pact. New York Times (1923-Current File), B4.