"DON'T TELL ME WHAT I CAN'T DO!" So we know he is not omnipotent, right?!
OK, I think we are at a point where we can start to compile a list of what we think or know the smoke monster can or cannot do.
What he can do:
1. LIE...He can Lie better than Ben or Sawyer
2. Manifest in Bodies. Dead bodies, presumably dead bodies where there is still a body,
3. He can manifest, into living form, memories he gathers through his handy telegenic photo technique.
4.He can manipulate better than the best manipulator i.e. Ben
5. He can "infect" people with an evil twisted sickness.
6. His warfare tactics seem to be limited to destruction by way of psychological twisting and manipulation and of course in smoke monster form, brutal force.
What he Can't do:
1. Seemingly, cross bodies of water
2. Leave the Island whenever he wants
3. He cannot personally kill the candidates by his own hand....or in smoke monster form
4. He seems to be repelled by the banyan trees??
5. He cannot drink water or any other liquid like wine (this is seemingly true as we haven't seen him take a gulp from the canteen yet) (BTW the water on the island seems to have life giving/healing properties).
6. He cannot confront Jacob on his own but rather needs to "turn" one of Jacobs own against him.
7. He cannot break the rules..whatever they are..
8. He does not seem to know what is going to happen next or be able to fortell the future. Proof of this: He did not know why or where the BlackRock came from. Went to ask Jacob. He seemed surprised when Jacob told him, "They're coming".
9. Based on 8 he doesn't know who is coming to the Island, and did not know "who" the package was..presumably
10. He does not REALLY know who all the candidates are and is guessing on some of them. Admitted this when he told Sawyer he didn't know if Kwon was Jin or Sun. I beleive he doesn't know Kate is a candidate.
11. He cannot be killed by weapons of mass destruction, guns or knives.
12. He cannot cross ashe, at least he can't while Dogen was alive
What else? I am sure there are more. As you can see the list of Cannots is long than the list of Cans, it seems the Candidates should start to figure this out and exploit his difficencies...