I had postulated upthread that perhaps it was to send a signal to various tribes of Others that it was time to make their move.

Ooops. Sorry. That's what I get for skimming. And skimming while a toddler is hanging on my leg, at that.

Question--do we know that the boat people who took Walt are really the Others? Maybe they're just working for the Others/listening to the voices that belong to The Others/just plain old pirates sailing the South Sea.

I also read Hurley's thumbs up to Walt as just general good will to anyone who would engage with him. However, that we were shown it means, to me, that they are one of the dichotomous pairs on the island (Jack and Locke being the other).

I think the people on the boat are the Others, and I don't think they want to get off the island. I think they drank the koolaid, and are the keepers of the island. However, I don't think it's their baby (or, at least, the people we saw aren't the ones in charge). There may be a Great and Powerful Oz. If so, I don't know whether Jack or Locke would be Dorothy. I don't see Walt joining the cult, unless JJ is really in love with the idea of child-as-mouthpiece-of-Eeeeevil.

There have been too many people who seem like they weren't supposed to be on that flight for me to think that anyone was actually not supposed to be.

Maybe the Others are just as much trapped as any one else by the "security system" -- maybe they can only go so far before they end up being taken back to shore. The island is protecting itself from being discovered by the out side world.

And the Others think that Walt can get them away with his creepy mind powers.

I like this theory. It still doesn't explain why they took Alex, but it still explains a lot.

How come everyone is so sure those Deliverance boat-folk were the Others? Did I miss something last night?

I thought it was implied by the French woman hearing the Others saying they were coming for the boy.

Walt's the annointed one.

How come everyone is so sure those Deliverance boat-folk were the Others?

Well, I put it in my head that Rouseau's talk of The Others wanting to take "the boy." and the creepy pirate dudes saying, "we'll take the boy" that they were the others. Rousseau is the only one who calls them that, though, so, the label means precious little. "The Others" is not very descriptive of a hell of a lot.

I think they are more guerrilla type fighters than all out attack people though (to answer, why don't they just storm the beach) an all out attack could cost them more than they think they can afford. So they infiltrate with Ethan, who only attacks Charlie and Claire. They kill Scott, coming from the sea, all sneaky like. They wait until Walt and very few protectors are 15 miles away from backup and escape.

It looked to me like the person who threw whatever it was that blew up the raft was female, and therefore maybe Alex. Could anyone tell for sure?

Looked that way to me too, Perkins.

A friend of mine thinks that Walt is just the latest in a series of young children stolen by the Others. We know of Alex, but Ethan could have been Alex's predecessor, and the line might stretch back further than that (maybe the slaves on the Black Rock included some children).