Well, significant enough for a character who was born sixty years after the events of the story. Entertainment Weekly has confirmed that Elijah Wood — who I guess has just accepted that he will always and forever be Frodo Baggins, even when he's seventy — will appear in both parts of the upcoming Hobbit… duology? (If that's not a word already, I'm making it one.) Of course, any fan of Tolkien's work will tell you that Frodo's definitely not in The Hobbit, so… what gives? Spoilers ahead:
Remember that part near the end of The Return of the King when Frodo is writing the story of the War of the Ring inside a book? The first part of that book he’s writing in contains a memoir by his uncle, Bilbo Baggins, which tells the story of Bilbo’s own great adventure. Apparently, Frodo will be reading Bilbo’s tale, and that will be the entryway into the proper story of The Hobbit.
Sure! I mean, this sort of sounds like the filmmakers are a bit worried that this film won't be able to succeed independent of the Lord of the Rings trilogy — even though they already share several characters, an over-arching master plot, and an audience who would never abandon them. You know, maybe we should just bring the whole cast back. Or, we could just watch all three movies again! I would do that.
Anyway, I trusted Jackson then, so I guess I'll trust him now.