Options: +[word]              Word is required in page
         -[word]              Word is prohibited in page
         [word]*              Wildcard (matches no more than 5 characters)
         "word1 word2"        Words must be in correct order
         title:[word]         Word must be in page title
         link:[URL]           Link is required in page
         host:[machine].[org] Page must be on *machine.org*

For usenet articles:
         from:[name]    subject:[phrase]   newsgroups:[part of groupname]