monitor mailboxes and/or newsgroups

 Xbuffy is a program that displays how many unread mails you have in
 your different mailboxes. You can have different titles for the
 mailboxes, and define what shall happen when a new mail arrives. It
 can beep and invoke a shell command, for example.
 .
 If you press mouse button 1 on the title associated with a mail box,
 a list of From: and Subject: lines of the mails in the mail spool file
 is shown. If you press mouse button 2, an arbitrary command is
 executed.
 .
 Xbuffy can similarly watch newsgroups via NNTP.