What are those colors on IE tabs?

I thought this was one of the best features in Internet Explorer 8, but not everyone gets the meaning of the colors on the tabs. The colors represent that the tabs are related, meaning that you followed a link from one page, IE opened another tab and assigned the same color as the previous tab, so that way the tabs that are derived from other tabs are now all grouped and it’s very easy to see this, very useful when you have multiple tabs open for different purposes. I just had to blog this because someone actually asked me what those colors were for, so I figured there’s more people who may have the same question.