Vita or Vitae?

I have never fully understood the difference between vita and vitae (or curriculum vita versus curriculum vitae). I found this relatively clear definition on Virginia Tech's career services web site:

A curriculum vitae (singular), meaning "course of one's life, is a document that gives much more detail than does a resume about your academic and professional accomplishments. Curricula vitae (plural) are most often used for academic or research positions, whereas resumes are the preferred documents in business an industry.

Note about plural / singular forms: "Curricula vitae" (vee-tie) is the plural form; "curriculum vitae" is singular. The informal shortened form, "vita" standing alone, meaning a brief autobiographical sketch (Webster's), is singular, while "vitae," is plural. The abbreviation is often used: CV or CVs.

I think this clarifies things a bit for me, anyone else have any thoughts?