* - creates an account with a certain keyword or series of letters, i.e. (.com, llc, etc);
* - posts a thread AND that thread contains a keyword in the title or post
* - posts a reply that contains the keyword
* - posts a thread tagged with a certain keyword.
In addition, they have requested the functionality to be alerted when the keyword appears in signatures, private messages, and visitor messages. I imagine something like this can run during off-peak hours and possibly off-peak hours can be specified in the admin panel.
Obviously ever forum owner may not need this but if you rely on your forum for communication within your corporate organization, then you would like more control over it just as you do with company email.