Earthlink assures me that this is a con-job. (I've been reasonably happy with them for seven or so years)
"Dear Earthlink Webmail Subscriber,
To complete your Earthlink Webmail account, you must reply to this email immediately and enter your password here (*********) as we are currently upgrading our services due to unwanted email. Failure to do this will immediately render your email address deactivated from our database.
THE EARTHLINK.NET TEAM"