mailq_applet is a GNOME 1 panel applet that shows the status of your outgoing mail queue. It's intended for dialup users who may connect, wait for the queue to drain, then disconnect. Having this on your panel is much more convenient than running mailq over and over again from a terminal. It works with Exim and Sendmail. If you use a different MTA, you may need to make some changes, but the code is so trivial that that shouldn't be difficult. This code is no longer used or maintained by its author.