Square Enix announced this weekend, at their annual Square Enix Party, that there's going to be another expansion for Final Fantasy XI - now in its fifth year - this one titled "Wings of the Goddess" and using such lines as "A tale once lost is about to be retold."
Right now the story behind this expansion is purely speculation, but from the video trailer released on the official Final Fantasy XI website, it looks like this may involve revisiting areas of the original world. It shows areas as they are in current Vana'diel, and then also fades out to what they originally looked like.
Perhaps this means some time travel will be involved. Nonetheless, if you're an FFXI fan, you'll want to keep your eyes glued to the Wings of the Goddess website, as it'll be updated with expansion info and images as the development progresses.