Google's personalized page, now called IGoogle, provides every user with a dashboard of what's important to them on one screen or multiple tabs.
After I installed the extension and restarted Firefox, I opened the sidebar with my options displayed. I noticed my personalized page couldn't fit in the sidebar. I had 5 tabs of data. I resized it and it took up half of my Firefox real estate. Yikes!
There was no way to slide through my tabs to access my content. If you do have a lot of widgets on your personalized Google page, all widgets will be flush to the left side of the bar. If you have tabs on your page, you may want to rethink this extension or putting your page in a sidebar. There are pages that utilize the sidebar...and then there are pages that do not.
The IGoogle sidebar looked like a good idea at the time, but after installation and using the extension for a week, it really didn't serve an absolute need for me. I actually uninstalled it after day three.