The post has been up for two weeks, but it's one worth noting, if only for the record: "Terminology: is 'Extraordinary Form' an acceptable name? And is it the official name?" (Rorate Caeli, November 6, 2012).
What occasions the post is the lingering puzzlement about how to properly refer to the old Mass. "Traditional Latin Mass"? "Extraordinary Form"? "Usus antiquior"?
The author of the post undertakes to make two points clear: (1) that the Holy father introduced the name "Extraordinary Form" in the motu proprio Summorum Pontificum in order to solve a liturgical law conundrum, and (2) that "Extraordinary Form," nevertheless, is NOT the "official" name of the Traditional Roman Rite. Worth reading, especially if you have questions.