Does anyone know if Google adds domains to its crawl list if they are known only through only known through Gmail email content?
A domain to which no one has ever linked and which was never submitted to Google or DMOZ has turned up in Google results.
Anyone know if they index emailed URLs?
It could have been that it was publicly listed after your purchase of the domain. I am not sure if google crawled mail for SERP but it would make sense as gmail is googles biggest social network and it would indicate trends but in a much more private conversation.