A little analysis with a nice little program results in the revelation that:
Must've been some good CC's in there.
Out of the addresses sent to, generally the highest figures were to mailing lists (in positions 1-2, 5-8, 10-12, 14-17).
Then there were personal ones -- my Dad (3), guy who lives down the Hall (4), the boss (9), gf (18), Mum (19) and some other friends (13,20).
Position 20 had 25 emails, position 1 had 155.
I think I need to send more personal emails. Of course, the figures are slightly skewed in that most people I know have a few email addresses (my gf has about 3 that she uses), so the figures are only really for addresses sent to rather than people.
Oh, as for USENET - no need to do any analysis, since I rarely read it, and post even less often.