Basically I have 2 Theories...
1. The Islands are really some psychological experiment. Whether it is still being performed or if it has gone terribly wrong, I do not know, BUT I think that is what it started out to be. I think the Dharma project is just a variable in the project to keep the islanders guessing. I think it was something set up to test the human psyche, see what we can take, how far we will go, and furthermore the results of being tested on. Maybe the plane crashed into the middle of the experiment that was already in progress, and the people running the experiment had to adjust their variables to keep it going???
Anyway, regardless of the variables, who's running it, etc. the basic underlying factor is its experimentation
2. I think the creators of the show are just running an experiment on us, the viewers, to see how many things we will come up with. I think they just keep letting strange out of this world things happen to the islanders to see what the public will think and say... Heck for all we know they do not even have a plan for the islanders... They may just wait to see all our ideas that we pour out, pick the best one and use it!!! who knows... but its genius marketing to have this much mystery surrounding the show because everyone tunes in!!!