Is it Web site or website?
Since the World Wide Web is a proper noun, we use initial upper-case letters, as we would with your surname, for example.
As for writing ‘Web site’ as one word, it is true that this is now the preferred way to write this, but it had not always been the case!
Some argued that since this is a site on the World Wide Web, we are really using a shortened version of ‘a World Wide Web site’.
Just as you would not write ‘buildingsite’ or ‘constructionsite’, some suggested showing the derivation of this phrase by retaining it as two words, coming from ‘a World Wide Web site’.
However, now, as language (and particularly that from the world of IT) evolves so quickly, mostly, we see: website
Incidentally, in any other context, the word ‘worldwide’ should always be one word, with no hyphen, just like ‘nationwide’.
Hey – here’s a funny thought – did you realise that the acronym (WWW) has three times the number of syllables (try to say it aloud) as the full version: World Wide Web? The full version has only three syllables, while the so-called shortened acronym has nine! Sometimes, shorter is longer!