To answer the questions:
I don't know whether the numbers include both incoming and outgoing. Certainly it includes outgoing. Whatever the case, incoming is probably a tiny proportion of outgoing.
NosyNed, I have a little free time tomorrow. If you're still interested in helping out with coding let me know via a post to this thread and I'll make the source code available to you tomorrow.
This is the monthly data I have from 2002 on. I have little data for May, 2002, because that was the month we switched webhosting companies. And the data for February, 2003, is low because most data for that month was lost after a server crash. Units are GB:
How the increased traffic is balanced between participation and lurking is impossible to say without correlating with message statistics. Moose has the message statistics, perhaps he could give combining them a shot.
The site appears to have more evolutionists than Creationists at present. Whether this is a trend or a fluctuation is hard to say.
--Percy