They explain it better than I could:
CoolMon is a small system monitoring application that displays current system data and performance statistics on your desktop. What s cool about it is that it does not have an interface of it s own, it rather displays the data in a simple text format right on your desktop, blending in with your wallpaper or background and not taking up any additional space. You can customize the information to be displayed and (on Windows 2000/XP) adjust the transparency of the display as well. Most of the application s data is retrieved from the Windows 2000 performance counters, so while CoolMon will work on Win9x, it will display much less information than on a Win2K machine, which it is primarily intended for. On Windows 2000, it will display Processor usage, Number of Processes, Number of Threads Used/Free/Total page file, Used/Free/Total RAM, Free/Total Disk space , Computer Uptime Date & Time, Computer name, User name, All IP addresses as well as Network read and write speed. CoolMon can also be configured as a server and a client so that remote machines can be monitored. Simultaneous local and remote monitoring is possible, as multiple instances of the application can be started. No install required. Great tool for remote server monitoring as well.