Checks an email address against a list of banned domains.

Deprecated functionality to determin if the current site is the main site.

Determine if user is a site admin.

Finds out whether a user is a member of a given blog.

Check whether a usermeta key has to do with the current blog.

Determines whether a user is marked as a spammer, based on user login.

Adds a new user to a blog by visiting /newbloguser/{key}/.

Corrects 404 redirects when NOBLOGREDIRECT is defined.

Notifies the network admin that a new site has been activated.

Notifies the network admin that a new user has been activated.