When an Elder Scroll’s gate is opened or closed and when a Scroll is picked up, captured, or returned, everyone will see a broadcast. It’s possible for a small group to escort a Scroll carrier, but the Scroll’s location will appear on the map—everybody in Cyrodiil will know where it is.

Judging by the wording in this answer, I would guess there will be more than one Elder Scroll, and I'm guessing they'll provide some form of buff to the faction that has one, increased stats and the like..