lexipixel - 7:46 pm on Jun 15, 2011 (gmt 0)
It looks like they are added by eBay, (since they appear in the heading of the listing not in the item description area).
There's an April 16, 2011 blog post on AuctionBytes about it with a few dozen comments... some people wondering if that exposes a seller to getting their personal info exposed on Facebook, others think it's good to expand market to social network for seller... the last one reads: "...I am sick of being forced to live my life in public. Get rid of this invasion of privacy!"
I guess it has upsides and downsides...