It's a word cloud: a piece of text is analysed and the words therein presented varying in size according to the number of times each word is used. There's a free tool for making them called Wordle (http://www.wordle.net/). You can customise fonts, colours, and shapes. Output formats available include PDF.
I suspect Rhiannon is correct, but that doesn't mean you couldn't make this in ID. I think, though you'd find it faster in Illustrator which allows you to just click and type instead of drawing a frame, then fitting the frame to the content.