whoru by Brian

This addon allows you to make whois queries from the address bar by typing "whois domain.com" (where domain.com is the domain that you'd like to query), and the resulting page will be the whois listing for that domain.

Also, 'ping somebody.com' will ping somebody.com.

This (probably) only works if you've got Google as your search provider. If it's real important to make it work more generically, let me know, and I'll .. Well, I don't know what I'll do, but we'll both find out when it happens.