Windows Vista's Gadgets provide a cool way to customise your desktop with handy tools and information feeds. I'm an enthusiastic Windsurfer so you can imagine my delight when I stumbled across WindGuru's windspeed gadget. It's cool because the gadget can be configured (via a pull down menu) to provide details for my local Windsurf spot.
The image below shows the gadget itself located at the top right of the sidebar, the Internet Explorer window depicts a web page containing many more gadgets :-)
Gads will be really cool for the not so savvy.
As these are safe for the most part, before Vista many wood-be XP gad type plug-in down loaders received more than they bargained for, oh yea Gad is short for Gadget!
Gadgets will be any other code in that the user MUST TRUST the author - that are cases where malicious gadgets could expose the security of the system.