Just click the button to scroll current page back to top.
There are several extensions that do the same in the chrome store, but I wanted something simple and lightweight -- just a toolbar button that does the job, without fancy animations and complicated options. So I made this.
Please, remember that this extension doesn't work on each and every page. It works in most sites (tested with twitter, facebook, deviantart and many others) but it will not scroll up browser's internal pages (settings, history etc.) and some complicated web pages. If it doesn't work for you, please, don't hate me too much. You can at any time remove the extension from your browser (go to the "Extensions" page and simply uninstall it)...
For Chrome and Opera 15+
Starting with version 2.0, you can now change the default icon to one of several predefined alternatives or even, if you want, you can set your own toolbar icon. That would be particularly useful if none of the predefined icons matches the Chrome theme you are using. To change the icon, just right-click on the scroll to top button and select "Options".