iGoogle gadgets interact with the user and utilize the Google Gadgets API. Some gadgets developed for Google Desktop can also be used within iGoogle. The Google Gadgets API is public and allows anyone to develop a gadget for any need. iGoogle recently added a new gadget named " What's Popular". It seems to be similar to Digg, Reddit, Stumbleupon. where you can vote the web pages and add content you find interesti
Be twittered has a gadget AND a moble gadget for twitter -- I'd love to hear how you like it. This means you may add a gadget to your homepage of igoogle to keep up w/ twitter on your start page. The mobile gadget allows you to put the app on your cell phone to track twitter. This is from 32 hours.