First, as I have written earlier, I think she may not want to be president and would prefer to let someone else carry the torch. She has said, however, that she would step in if she didn't see a candidate likely to beat Obama. With all due respect to Hermann Cain, I don't think he is that candidate. He has lots of expertise as a businessman, but none in government, a different beast. Sarah knows this as well: she has actually run for office and won.
Second, as far as not needing a title, Greta very wisely challenged Sarah. There is a difference between having dinner with the prime minister of Israel and telling him that the American people love his country and sitting down at the table as president of the U.S. with all the actors and players, thus in a position to further Israel's interests. Sarah is not so innocent and naive as not to know this herself.
Third, her secrecy regarding her intentions is a good sign: it means her opponents do not know where she stands. She keeps her cards close to her chest. That is an excellent operating position when you consider the opponents she will face as president of the U.S. Obama gave away everything from the get-go, telling our enemies what he would do. And guess what? We are weaker now not only as a nation but also as an international player. Sarah Palin will not telegraph and certainly not proclaim loudly in advance what America's game plan is.
Fourth, RichardNC mentioned something very important in a comment on Conservatives4Palin: Sarah has to have all her ducks lined up perfectly. Otherwise, her enemies will exploit any "technical" mistake she makes by filing suits with the FEC.
Finally, I would say that she has never said she would not run. If she decides, she will be whole-hearted. And because she will be whole-hearted, she will win. Thus, her answer to Greta: Of course, she can beat Obama.
Keep the faith!