I am constantly amazed by the members names I remember from RT, who have had this same problem.
Most of my extended family & friends have never been into the forums, and have never had a phishing email in their lives, however, most of the people I know who have been long time forum contributors, seem to have their email accounts spammed, even though they have been exclusively used for ebay and PayPal, and no other source.
We did an experiment on another site, and within a few posts, one of the baiters on the site declared to the poster, " But is she the master of her own Domain ", In answer to a post where the woman declared she was the master of her own destiny since her divorce. The woman was accused of being me, or a close friend, so they offered the that as evidence.
An obvious reference to the fact I set the experiment up with an email addy from my domain, and as the Domain is easily accessed, but only if you know the name, or email address.
The email address could only have been known by the Administration, as it did not send or receive any emails, only the registration on the site, and it was the first time the email address had ever been used.
Auction sites forums are inhabited by employees and their friends, and as there is so much money to be made by never buying and selling, it's a sure fire bet they will never be caught, because any evidence disappears with a click of a mouse.
It also seems to go on rotation, almost like somebody has a data base of names, and works their way through them, so it can't be pinned down to an event on the forum, but we should be aware, they are ever present & watching, and for anyone who shows negativity towards a site, or certain members who are active on the forums of a site, and stand up against bullies, are certainly on the hit list for spamming and trolling.