Purchasing bitcoin off Mt. Gox was not an easy deal, if the quantities were largish. Over 10K$ (back then) required a KYC (see
https://web.archive.org/web/20121009011724/https://mtgox.zendesk.com/entries/20490576-frequently-asked-questions). That is of course a large amount, but the point here is to highlight the procedure for those cases. I found interesting to read.
Additionally, this quote corresponds to a few years after its opening, but it highlights how the process was tedious and lengthly, at least with large amounts:
<…> So they would have to go directly to the Japanese-based exchange, open their own account, and become customers. Which meant new headaches; to wire that kind of money to Mt. Gox, there were hoops they’d have to jump through. First, they had to scan their passports and mail physical legal documents to Japan—actually, to a P.O. box in Shibuya. Once their information made it over the ocean, they would still have to wait weeks for it to be processed, because the onboarding queue at Mt. Gox was so backed up. <…>
Quote from "Bitcoin Billionaires" - Ben Mezrich
Mt. Gox before selling bitcoin (card game trading):
https://web.archive.org/web/20090812073342/https://www.mtgox.com/Mt. Gox selling bitcoins (2011 (not quite 2010, but near enough)– interesting to browse):
https://web.archive.org/web/20110203031942/https://www.mtgox.com/They also had resellers that bought off Mt. Gox, and sold locally (i.e. BitInstant - 2011-2014).