Be consistent, and just start writing [Re: 3rd person singular neutral X 3rd person plural ?]
On Thu, 15 May 2008, email@example.com wrote:
> 'BHP Billiton are the world leaders in mining')
This bit isn't a big deal; entities whose names clearly indicate a
group use plural forms. Entities whose names do not, use singular
forms. 'Hewlett and Packard are', 'Debian is', 'The FooBar Group are';
pick one, stick with it for the same document. If you find the
singular annoying, make it unambiguously plural: 'Debian memebers
are', 'The fine people at Debian are.' Above all, use the matching
pronoun: 'It is', 'They are.'
Follow my rule of grammar: when mired in grammar, obviate.
In any case, neither usage matters terribly much; get down to writing
first, and worry about the stupid vagaries of English grammar as
practiced by different regions later. Most of the fiddly bits no one
besides serious grammar nutcases are going to care about much, and
they aren't going to read our press releases, or are going to be the
ones editing them to fit their particular notion of grammar for
publication in their region, anyway.
Only one creature could have duplicated the expressions on their
faces, and that would be a pigeon who has heard not only that Lord
Nelson has got down off his column but has also been seen buying a
12-bore repeater and a box of cartridges.
-- Terry Pratchet _Mort_