[Sam Bauers]

This is a complete overhaul of the restrict registration plugin, featuring:

• Whitelist – limits registration to email addresses with specified domains
• Blacklist – stops registration of email addresses with specified domains, perfect for dealing with repeat bozos from a known domain name
• Wildcard domains – specify wildcards in lists, e.g. *.com, *.example.org
• Whitelist vs. blacklist resolution – logically deals with conflicts between whitelist and blacklist when wildcards are used (see configuration section in readme)
• Admin page – edit the lists in the bbPress admin area
• Show whitelist option – optionally show the whitelist domains on the registration form

http://bbpress.org/plugins/topic/44