When Sayid is first "claimed" Dogen mentions that he'd watched it happen to Claire (actually he said "your sister" to Jack but it's probably a bit late to introduce another sister or even a nun). Watching Sayids transformation in this episode and Claires behavior in the previous one gives us some insight into what this means. Creepy detachment, innapropriate smiling, bloodthirsty violence.
We also know that when Sayid shot Ben (30 years ago) that Richard took the kid to the temple where presumably he went into the pool as well. We've always assumed that going into the pool made him "an other" but now I'm wondering if that's so. He is creepy with a weird smile and he can be ruthlessly violent at times but he just doesn't seem anywhere near as weird as the other two.
So is Ben "claimed" like Sayid and Claire or is he something altogether different?