User blog comment:G0LD3NF1RE/E3 Elder Scrolls Online Roundup/@comment-68.6.130.235-20130623012311/@comment-98.114.41.129-20130702085214

A lot of people replying to you seem to not understand that "single-player" and "offline" are not always the same thing. I'm not sure if you do, either, so I am going to explain:

Yes, there will be plenty of single-player content. I am not completely certain, but I think I heard/read that the entire main storyline is something you can play on your own. However, you must be online to do it, so you will need a reliable internet connection. There will be some content that you will not be able to do on your own, and that will require you to enlist the help of other players (e.g. dungeons).