The Windows 7 sidebar includes some major improvements over Windows Vista sidebar. Firstly, the sidebar itself is turned off by default. Secondly, even though you can turn on the sidebar, it doesn’t eat into your desktop space as before. It remains as a transparent almost non-existent strip on the side, quietly on the desktop under your open windows. Thirdly, you can drag the sidebar gadgets away from it and place it anywhere on the desktop.
The same Windows 7 sidebar with exactly the same functionalities can be enjoyed on Windows XP and Vista with Thoosje's Windows 7 sidebar. The sidebar includes about 20 popular gadgets by default such as sticky notes, calendar, the obligatory analog clock, media player, POP3 mail retriever, RSS reader etc. The sidebar uses the same .gadgets file as the original Microsoft sidebar, so all gadgets on Windows Live Gadget library are compatible with Thoosje's Windows 7 sidebar.
Memory usage is around 60 MB, and CPU utilization is light. You can easily use it even on old PC’s without any major issues.