Apparently it's not that simple. I am told Ebay will give your contact info out to prospective bidders if they ask for it, and provide this form to request it.

Here is a comment from Ebay on the subject:

Typically the seller shouldn’t have anything to worry about, as we only allow members of eBay to request contact information. We allow any transaction partner (including a bidder) to request the buyer/seller’s contact information. This includes a phone number, and the address. This is for all members of the site, and something we’ve found be very helpful overall. There’s not a way to opt out of this as we expect it of everyone on the site, namely because we’re only a venue and don’t buy or sell the item directly.