Whenever a hot new product comes out, there are always auctions for domains and email addresses with the name of the gadget in them. Like say the new Acme Widget is introduced, so someone promptly registers "acmewidgetworld.com" and sells it. That is just fine. But please be careful about email addresses. Most free 'webmail' providers (like Hotmail, Yahoo, and Gmail,) prohibit the transfer/sale of their user IDs. This means while selling "acmewidgetworld.com" is fine, selling "acmewidgetuser@yahoo.com" is not. This violates Yahoo Mail's Terms of Service, which states:

12. NO RESALE OF SERVICE You agree not to reproduce, duplicate, copy, sell, trade, resell or exploit for any commercial purposes, any portion of the Service (including your Yahoo! ID), use of the Service, or access to the Service.

Gmail and Hotmail have similar policies. So, before you bid on that new "widgetrocks@yahoo.com" address, think again. Yahoo has every right to terminate that user ID if they find out it was "sold".