Already received my first SPAM, I was interested to see which disposable address it was sent to, but the problem is (and I didn't consider this) is that if the sender uses BCC instead of CC or TO then I don't think that I can see the email address they used for me.
Still - I'm pretty sure I know how they got it. First of all, I've created a brand new Hotmail account and I've made sure that I don't post the email address anywhere, so I know it's not that email. That having been said, I've only created two disposable email addresses and used them as a test. The first was signing up with Apple Support, so I doubt that it came via that route. The second test was the disposable email address that I posted here, knowing that bots can visit sites and harvest email addresses. By the process of elimination, this must have been the source.
On a somewhat interesting side-note, today, I've found that all of a sudden, I have 23 hits, all from the same O/S, country and browser, which leads me to believe that it's somewhat likely the same source. Perhaps this bot is checking other pages on the site for other email addressed, but I don't think so. Just from the posts that were viewed and the fact that they are older, I suspect that this is an individual how has stumbled upon TecHumanity. I can't be sure, but that's what I think.