@okie,
Do a Google search on "change.gov"
Here are a few articles to get you started:
http://venturebeat.com/2008/11/05/changegov-is-coming-and-has-obama-picked-his-cto/
http://www.techpresident.com/blog/entry/33001/blue_state_building_obama_transition_site_change_gov
http://www.demconwatchblog.com/2008/11/obama-biden-transition-project.html
As for the email it had two sentences. The subject line was
www.change.gov.
The content said "The official website of President-Elect Barack Obama" and gave a link to the venturebeat.com article as verification. Don't believe me? Send me an email at the address in my profile and I'll forward it to you.
So, it didn't come via an organization chart. Someone in the grassroots group read it in the news and emailed the info and link to the rest of the group. We did that sort of thing for the last two years, reading news and columns and sending each other links to them to help spread the information.
By the way, we then spent the next few hours emailing back and forth about how the site wasn't working for some of us and maybe it was because of the high amount of traffic it was suddenly getting.
Now, if you do what I suggested and do a Google search on "change.gov" you'll find pages and pages of mention of it both in the Google News section and in the general web search engine section.
Technically you are probably right, someone from HQ or Blue State Digital probably sent out a press release to announce the creation of the website.
And you still have it wrong. Most communication with the campaign flows from the bottom up, not the top down. About the only email we got directly from the campaign were requests for donations. I can honestly tell you that I didn't read most of them, I just sent them to the spam folder.