To be proficient with Tagxedo please go through the blog posts. Check
out at least the two mini tutorial (search for Tagxedo portrait and
Deja Vu is also explained in one of the blog posts. Basically it
allows two separate Tagxedo runs to assign the same color to the same
word. So if you say run Tagxedo on two speeches by two presidents, you
can more easily identify the same word in the two Tagxedoes (since
they'll have the same color).