
Originally Posted by
wige
You mentioned the page has a domain name pointing to it. That may be how Google found it. I have heard enough rumors to believe that Google may be getting proactive trying to find and "preindex" if you will new domains, sometimes within hours of them going live. Of course, there is always the possibility that someone else owned the same domain at some point in the past and Google found it that way.
Of course, there are some theoretical ways Google could possibly discover a page, although Google denies they use these methods - if you traveled from the page in question to a site that has Adwords or Analytics installed, Google might be able to see the URL in the referrer tag.