I've noticed an interesting anomaly when running Chrome 40.0.2214.10 beta-m (64-bit) on Win7. Admittedly, I have yet to test this on other browsers.
In the screenshot below you will see to eBay item pages -- the first has a title which renders as a Serif (is that Times New Roman) in the Chrome Title Tab. The latter renders in the standard Sans-Serif Chrome font.
The URL for the first example is here: http://ebay.com/itm/301399607776
My principle question is whether or not this is something that I can reproduce using any combination of markup, javascript or other file or server-side settings -- or whether or not this is some kind of unusual bug or setting in my local browser settings.