It's a test feature. It's been in Word for a long time, and I've known about it for a long time too (sorry). You can vary the numbers to get a different number of results. The first number is the amount of lines, and the second the amount of times the sentence is printed per line.

For instance:
=RAND(1,1) just returns a single generated phrase
=RAND(2,1) generates two (rows) of text
=RAND(100,1) generates one hundred rows
=RAND(1,2) generates two (columns)
=RAND(2,2) generates two rows each with two columns

It is somehow similar to lorem Ipsum ...
The sentence "The quick brown fox jumps over the lazy dog" is a sentence that contains all 26 letters of the roman alphabet. As such, it's a convenient test phrase when testing things like fonts and markup...

In microsoft office 2007 word there is another text... instead of "The quick brown fox jumps over the lazy dog"



In Microsoft Office 2007 word =lorem() does print lorem ipsum...