Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
(a): Coverage comparison between Twitter and Facebook. (b): Twitter coverage by publication year and discipline. (c): Facebook coverage by publication year and discipline. (d): Twitter coverage by user type and discipline.
