"Time Travellers"

In essence: Oceanic 815 flew through a rift in the time/space and are now lost in the past somewhere.

Support for the theory: We haven't seen anyone from outside the island looking for their loved ones. Would a distress signal really play for 16 years with no one finding it? How outdated are the records in that hatch?

This theory got some big support at the 2006 ComicCon in San Diego. In response to a question about how long season three would take place (as one took 42 days, two took 23... interesting, that), as part of the response, Damon Lindelhof replied with something to the effect of "That's assuming time moves the same on the island as it does off." (If someone has the exact quote, that'd be great...)

Poking holes: The records may be outdated, but I know I'd love to have a washer/dryer as shiny and new as the set they have! We've met Alex now, and she doesn't seem to be 16. With the introduction of Penny, we know (well, assume) that someone's looking for the island.

In addition, anyone who has followed the commercials for the Hanso Corporation and visited the website will see that they are still up and running, and hiring. Why would a decrepit company from the past still be hiring? Perhaps they don't acknowlege the "lost" island anymore, but would that make it a time hole?

Also, yet another theory given a shout-out.

-The writers have previously stated that there's no "time travel", and the idea does seem too high concept for the show. So whatever they mean by time passing differently on the island, it has to be in subtler ways. As in: No Twilight Zone rips in the space-time continuum.

As an aside to the time theory, consider how the Lost story is being told. We are learning about the past of each character through flashback. Just as the film Memento uses a backwards chronology to illustrate the short-term memory problem of the protagonist, perhaps the way the story is told in Lost is relevant.