When using modern versions of internet browsers, such as: Google Chrome, Internet Explorer 8, Opera 10, Safari 5 and Firefox 3 you may notice that the scroll bar is not visible if the website fits your resolution, for example www.google.com does not need a scroll bar on most resolutions. The scroll bar only appears when the page needs to be scrolled, for example when viewing the news feed of Facebook.
Why am I saying this?
Some time ago, I was testing a small website I was developing for my game development team www.barbaganngames.com and I noticed that when I view the Team Page, the template of the website moves slightly (about 10 pixels) to the left. I spent about 2 hours trying to debug this issue, and checking the HTML and CSS of my website to be sure that there is nothing wrong. Then I realised it was because of the scroll bar appearing and disappearing in Chrome and not because of a bug in my website.
I hope this helps you when testing your site, and you don’t waste time debugging the website like I did.