Twitwinner allows you to compare up to 5 different terms (words) to keep tabs on their Twitter popularity.

Twitwinner offers a widget for your website that will display “Live” popularity stats about the topics you have chosen.

You could compare Pepsi vs. Coke to see which one is more popular on Twitter.

Or you could compare Chevy Ford and Dodge

The widget is completely customizable. You can set the height and width. Set background and font colors using Hex code.
You can also pick a title from a drop down or create your own custom title.

This is actually quite a useful tool if you want to show a quick comparison of the popularity of just about any topic you may be writing about.

Check it out at http://www.twitwinner.com/widget.popular?q=google_facebook