What is Literature, Really?

From Shakespear to Shanely, Kant to Cosmo, or even Plato to Playboy people have began to wonder, and some not so recently, what really qualifies for that ever exclusive and prestigious club of "big L" literature. Is this blog literature? Is a myspace comment? what about a journal entry? Well, according to Barry Laga, these are all equal candidates in the race. Laga's theory is that for every past attempt to define literature there are documents out there that meet those requirements yet still are publicly held in a lower relm of the literart world.
Now although I do agree in part with this idea, I still hold as a personal belief that literature (excuse me, Literature) is somthing that goes beyond telling a pre-pubesent girl the ten secrets to drive men wild. "Big L" Literature is somthing that affects many people consitently on the same intellectual level, and although Cosmo may satisfy this as well I don't think it still matches the quality of let's say London's epic Call of the Wild.
One point that I think must be raised here is that thinking of literature in this reltivistic sense really leaves loopholes any time a solid, concrete, absolute definition is attempted. What I personally qualify as literature is not going consistantly going to match with the next person's list and I think that will apply no matter who sets down the laws of lit.
So, I guess on the whole I am really saying that although I think it is admirable to challenge the established definition with new ideas, I don't think I entirly understand the point since it seems to futile in the end. Then again, that's just my opinion and I could be entirly wrong.