As for the island being invisible, how come Michael and Sawyer saw it when returning back to the island, on what was left from the raft? (I know that's about 2 seasons old, but it just came up to mind. )

Why did Juliet tell Ben that it was no big deal that they were floating around on the sailboat? She said something to the effect of they'll drift around in circles and not get away. I know this applies to Desmond's boat, Elizabeth, and not the raft Michael built, but wouldn't the raft do the same thing as the sailboat? The following transcript bit is from "The Glass Ballerina":

COLLEEN: Am I interrupting something?

JULIET: Would it really matter if you were?

COLLEEN: We have a situation -- Ryan radioed in -- the Iraqi found the decoy village.

BEN: Good, it's what we wanted.

COLLEEN: Ryan followed him back to the shore and they have a sailboat.

BEN: How?!

COLLEEN: I have no idea.

JULIET: So they have a boat -- sailing in circles will keep them busy.

COLLEEN: They could find us. [long pause] Ben?

BEN: I'm thinking. How quickly can you put together a team?

COLLEEN: Within the hour.

BEN: Then don't waste time talking to us. [Colleen starts to exit] Hey Colleen, I want that boat.

__________________

`Dear, dear! How queer everything is to-day! And yesterday things went on just as usual. I wonder if I've been changed in the night? Let me think: was I the same when I got up this morning? I almost think I can remember feeling a little different. But if I'm not the same, the next question is, Who in the world am I? Ah, that's the great puzzle!'

-- Alice, from “Alice’s Adventure’s in Wonderland”

Through the looking glass refers to Charlie Contacting Penny problaly.