A page that enumerates user opinions on why Wikipedia is not so great.
And yes, it's a Wikipedia entry.
It also turns out that Wikipedia also has a separate page that provides more formal criticism of this free encylopedia.
I think, it is precisely this quality of this open-source reference guide, that redeems it. It might not be great (and most who use it, know that) but it's still good. And it tries really hard and honestly to be the best.