Snarl!

Growl for Windows is a Windows-compatible version of Growl , a notification system for Mac OS X.

An institutional/enterprise-scale distributed real-time messaging and notification system. Zephyr allows users to send messages to other users or to groups ofusers. Users can view incoming Zephyr messages as windowgrams(transient X windows) or as text on a terminal. Zephyr can optionallymake use of the Kerberos version 4 security library or the Hesiodservice name resolution library.

AlertPOP! - Add non-intrusive popup messaging to you application.

Canonicals on-screen-display notification agent, implementing the freedesktop.org Desktop Notifications Specification with semi-transparent click-through bubbles.

Growl forked prior to going commercial, working with OSX 10.7 lion

Notifo is a mobile notifications platform empowering developers to build their own services with a scalable and reliable notifications API. The Notifo API is a simple and affordable way to add notifications to any web app or project.

FP-Notifier has been renamed to FP-QUI.

Notica lets you send browser notifications from your terminal to your desktop or phone. No installation or registration is required.

Toasty lets you receive push notifications on your Windows Phone 7 device while you are on the go. Some of the key features are:

Notifu, a free open source pop-up balloon utilityNotifu is a tool that displays a yellow pop-up balloon in the system notification area, better known as the tray. It is free and open source, give it a try! Notifu uses the same API that Windows uses to show pop-up balloons. You see them when you add a device, such as a wireless network or a USB drive, or when certain system events occur, say, every second Tuesday of the month...Notifu displays a message. So in its simplest form, the message is the only required arguments. Use the /m switch »