User blog comment:JAlbor/E3 2013: Answers from Elder Scrolls: Online/@comment-5166842-20130614150655/@comment-7153552-20130614164040

Most MMOs don't have a single-player campaign (this is changing slightly for some games coming out soon), and no. If the game is sub-based you will need to pay to play. However, I doubt that ESO will be, and sincerely hope that it will not be, sub-based. It just doesn't make sense in today's market.