I received the email from United and read this down in their terms.

• This offer is only available to the initial recipient of this e-mail.
• This offer is available to new Cardmembers only; existing United Mileage Plus Visa Cardmembers are not eligible.
• Mileage Plus miles will be awarded only to accounts that are open and not delinquent on the statement Closing Date.
• The United Mileage Plus Visa card is issued by Bank One, Delaware, N.A. which reserves the right to add or delete benefits and services at any time without notice to Cardmembers.
• An annual membership fee of $60 applies. First year fee waived.