I got peeved with Corning the other day when I found out they let another company produce Pyrex-brand glass under license which is not borosilicate glass. The whole point of Pyrex was resistance to heat, which you don't get with the cheaper soda-lime glass. At least I learned how to tell them apart (soda-lime has a blueish color, and borosilicate is clear).
http://www.anchorhocking.com/Bakeware_Facts.html#BORSILICATE