So many of those questions really got answered through out the show if you pay close attention. The dharma food, Walt's appearing, Christian's appearing off the island, and why the psychic said Claire had to raise Walt were some of the ones that did not get answered. However I would say 50% of those got answered and another 25% easily fall into the "is that really important at all category." People seemed to nitpick questions with Lost a lot. Obviously some of those on that list were jokes, ie Expose, the polar bear in walt's comic, etc, but only a handful of those would fall in the genuine unanswered questions. The article in the last link was a good read as well. I agree. If secrets to the island were the only thing the viewer was interested in, then they missed the point of the series. I just thought the video was a good recap of all the "What does that mean?" moments.