Working at QC for Mahalo needs more than a good foundation in grammar. Pages are reviewed for grammar and spelling, of course, but that's just the first step. They also need to be aligned with Mahalo's formatting and style conventions, so that- no matter who writes them- they are a consistent part of a whole. Every actor page should have the same basic information, in a uniform order.
However, those are not the most important things a Mahalo QC-er does. Each page should contain accurate information, presented without bias or opinion. It's sometimes difficult for a writer to tell when they are inserting too much of themselves into a page - and it's the Qc-er's job to find and eliminate any bias...as well as to teach the writer how to avoid it in the future. Sources need to be checked- to ensure that the information presented is credible. Writing needs to be concise - so filler needs to be removed. And the page also needs to present the most important information about the topic- so that it provides value to the user.
So, a QC-er needs to be have the skills of an English teacher, a journalist with a knowledge of AP Style, experience with Mahalo's formatting and style conventions, an Internet researcher's knowledge of good sources, and the skills of a winning Trivial Pursuit player- to have that little bit of knowledge about everything that allows them to determine when a piece of information just doesn't seem to fit and warrants further evaluation.