Digital watermarks and trading cards

A method of playing a fantasy role-playing game involving playing cards, wherein:

• at least one of said cards conveys a plural-bit steganographic watermark;
• a first player presents a watermarked card to an optical input device, and is issued a virtual card corresponding thereto;
• and
• the game provides for the conquest of said virtual card by a second player, and its consequent loss by the first player.

A trading card comprising a substrate and an image formed thereon, wherein:

• the card conveys a steganographic watermark representing plural-bit digital data,
• the trading card has a sports player depicted thereon;
• and
• the digital data serves as an index to a data repository, said data repository having stored therein information comprising at least the following, or a hyperlink to at least the following:
• recent auction prices relating to said trading card.

A method comprising:

• issuing a trading card comprising a substrate and an image formed thereon, the card conveying a steganographic watermark representing plural-bit digital data;
• receiving data from a first custodian of the card when said first custodian presents the card to a system equipped with an optical image sensor and the system decodes the plural-bit digital data from the steganographic watermark;
• and
• entering information in a database that associates said card with said first custodian, said information including electronic address data corresponding to an internet resource associated with said first custodian.