Goodgulf:
its/it's - this a rule breaker. In almost all cases, 's means possessive. In this case its is possessive and it's is it is.
That's a little misleading Goodgulf. Though possessive nouns always have the 's, possessive pronouns never do. "Its" follows the same pattern as "his", "hers", "theirs" et cetera.
As to the feedback question; I think the hardest part of providing a critique is that it takes more work. That is, it's easy to drop a short, positive remark ("Nice story, I particularly liked the descriptions") than a short, negative remark ("Eh, this story fell flat, I didn't like the descriptions"). The first an author can look at and feel fine about; the second an author will want an explanation for. To leave negative critique requires more explanation, more work, and is likely more time consuming than most 'net readers want to devote.
So, while I'd be happy to have a full on critique, I'd be distinctly dissatisfied with a critique that was unjustified or unexplained.
-LK