TrayIt! is described as '- minimize to the system icon tray any program (Outlook Express, Notepad, Word, Internet Explorer, Sunbird, Thunderbird, Opera, OpenOffice etc.) and get more room in the Taskbar!' and is an app. There are more than 25 alternatives to TrayIt! for a variety of platforms, including Windows, Linux, PortableApps.com, File Explorer and Thunderbird apps. The best TrayIt! alternative is SmartSystemMenu, which is both free and Open Source. Other great apps like TrayIt! are RBTray, RBTray Fork, KDocker and SmartContextMenu.
FireTray is system tray extension for Linux and Windows that targets Mozilla Firefox, Thunderbird and SeaMonkey.
Chameleon Window Manager will allow you to control the windows of your programs using customizable buttons added to the title bars of the windows (Always on Top, Minimize to Tray, Minimize to Caption, Specify Transparency, Position window at left/right of screen).
Process Manager for Windows is a utility which allows you to to set process priority, minimize windows to the system tray, and more—all via taskbar window button right-click menus.
Moo0 WindowMenuPlus lets you have extra useful menus in every windows "system window menu". Its the menu that you can access through right-clicking on any windows title bar or taskbar button. This tool can add extra menus there such as "Keep on Top"...
Make all windows but the active one transparent.
Features:
Minime is a tool that allows you to minimize applications to the system tray using a simple hotkey. What makes this tool somewhat unique is that it keeps your system tray clean by minimizing all applications into a single tray icon.
Small little program that allows Windows 2000/XP users to make any window transparent. Right-click on any window or press the keyboard shortcuts (Control + Shift + [0-9]) to make any window transparent. Its that simple.
Clicky Gone allows you to hide your selected windows from view, this includes the taskbar button associated with the application. This utility particularly helps with protecting your privacy by hiding things like your browser with banking details up and someone walks in on you.
Min2Tray - a utility for MS WindowsTM NT and higher to minimize and hide a window to system tray area of taskbar as icon.
GhostTile is the most popular Mac alternative to TrayIt!.
France
EU
Russia
Firetray only deals with Mozilla applications.