Where it came from
On 22 November 2009 an account named satoshi, carrying the rank Founder, posted the first thread on a new board: "Welcome to the new Bitcoin forum!" The post gave the address of the previous one, hosted on SourceForge, and said "I'll repost some selected threads here and add updated answers to questions where I can." That thread is still readable at its original topic number.
For the next several years this was where Bitcoin happened. There was no company, no conference circuit and no press. There was a forum running Simple Machines Forum software, and a few hundred people arguing on it.
What happened there
Two threads carry most of the weight. On 18 May 2010 a user called laszlo wrote "I'll pay 10,000 bitcoins for a couple of pizzas.. like maybe 2 large ones so I have some left over for the next day." On 22 May he came back and posted "I just want to report that I successfully traded 10,000 bitcoins for pizza", with a link to photographs and a thank you to the user who had ordered them. That is the whole record of the first documented purchase of a physical good with bitcoin, and it is four lines long.
On 18 July 2010 an account named mtgox opened a thread titled "New Bitcoin Exchange (mtgox.com)" with the text "Hi Everyone, I just put up a new bitcoin exchange. Please let me know what you think." Mt. Gox went on to handle most of the world's bitcoin trading and then to fail, and it was announced in a forum post asking for feedback.
What it is now
Still running, still on Simple Machines Forum 1.1.19. The index reported 67,023,893 posts in 1,439,569 topics by 3,750,048 members on 21 August 2026. The administrator account is theymos, registered in February 2010. No legal entity has been established behind the site, which is why the structure here is left undocumented rather than claimed as absent.