That's fair, but is it really so much work to enter three extra keys on a url? That doesn't strike me as a convincing enough reason not to attempt a brand change, if it otherwise makes sense. (Unless there are many frustrated mobile users somewhere who've decided they've put up with long urls far enough!)

Using an article such as "the" in a brand typically indicates a desire to lay stake on a common noun as a proper noun, or at least the definitive instance of the noun. It often doesn't make sense when your brand is obviously a proper noun or otherwise unique already, but I suppose there's plenty enough newspapers having a variant of "Guardian" in their titles to warrant a push to definitive-hood.

Edit: A friend also pointed out that "guardian.com" is already taken by another established organization. I think that trumps my silly grammatical analysis :P