One of the things I have found myself needing over and over again as I design websites is “dummy text” or “filler text”, that looks like real content, that I can use to fill up a page so it gives the client the feel of a finished page, text and all.
Filler text matters because it allows you the designer to get an accurate feel of the balance between design elements and white space, and to see the relative weight of the text on the page, compared to other design elements. I use it all the time.