How do I check if a user is valid?

[podgryfami]

How do I check an email to verify it is not Spam?

[entegris]

Type in the user's ID (nick) of the user in the window found at this address:

http://www.ebay.com/sch/ebayadvsearch/?rt=nc

down  below check the "Specific sellers (enter seller's user IDs)"