Language evolves. Dictionary spelling and definitions reflect established usage by the
masses. Example: The now mature word "screenplay" transitioned over the years from the words
screen + play, as evidenced in credits from old movies and early TV shows.
Current references to the relatively nascent term "web site" vary. Merriam-Webster Unabridged and Newsweek
keep the words separate, while TIME magazine uses website. The Associated Press Stylebook
(the "journalist's bible") uses Web site.
Which do you believe will eventually win out?