There is an interesting post at SEOChat.com's forum in regards to the use of the correct English term "Web site" versus the accepted but not correct term "Website". The larger question in play is when to use incorrect spelling of a term when you know a large percentage of people searching for the term misspell that term.
I would love to hear from the copywriter people and the usability people here on this.
The thread can be found at SEO Chat's forum and is named "Website" vs "Web Site".