The Mozilla Foundation’s Firefox browser plans to discontinue support for SSL version 2.0, which has been superseded by SSL3 and TLS. The only sites that would be affected by the Firefox decision would be those that connect using only SSL2, and not SSL3 or TLS. An analysis of data from Netcraft’s SSL Survey suggests this is about 1,000 sites total, including about 200 that receive substantial traffic.

Netcraft’s SSL Survey provides detailed information about encrypted transactions and e-commerce, including the growth rate for SSL-enabled sites, and which operating systems, server software and certificates are most widely used on these sites.