I know, that one is tough!
I personally have gone back and forth. When it's written as their logo, it's CamelCase:
http://www.waterfrontmedia.com/about-wfm.aspx (see in the list on right side?)
When it's written as text, including on their own site, it's two words.
Julie seems to be ruling that it is CamelCase, but .... I could go either way (and have used it both ways).
How's that for a non-answer?
~Nicole