+1... Just because you have a use for it doesn't mean no one will. You need to rate on the functionality of the tool and how it matches up to what the dev described. Not your personal need for it. Maybe if you would of read the description in the first place. You would of known what it did and never made it to the point of commenting. Please stop being so ignorant.
PS; Even if this addon was garbage (its not but if), I don't see how you people think you can complain. He is writing this (which takes time) then letting you use it for free! If its not good enough for you then lets see what you can make and how you feel when people under-rate your work for no reason.
Unless I'm misunderstanding something here, I don't see the point of this add on either. If you are using Windows 7 and you want a movable Google Calendar button in Firefox 3.6.6, simply type Google Calendar into your address bar - instead of a URL and hit enter. Google will automatically take you to your Google calendar page. Then, when you see the Calendar icon that appears to the left of the URL, just click it and drag it onto your Firefox toolbar. Voila! A movable button that works
I do not see the point of this add-on. If you want a small icon to get you to GCal quickly, just do this: Bookmark Google Calendar on your bookmarks toolbar. You will notice that Google Calendar provides its own favicon. Edit the bookmark, remove all text from the Name field, et voila, you've got exactly the same functionality without an extra add-on weighing down your browser.