Is it a good idea to include the writing of a wikipedia article(s) on your CV before grad school application? I am considering applying for graduate school at some point, and I am wondering how academia looks upon contributions to Wikipedia.

Essentially, the article will be a dedicated to a very specific subfield of the physics of spin glasses, with seminal papers written on it in the 1980's. It has somewhat of a "cult" status within a small subset of the field, and the inspiration for writing it is:

(a) This aligns strongly with techniques I aim to use for my further research, so it seems like a good way to share what I know with the community.

(b) This seems like there is a legitimate need for advanced undergraduates/new entrants into the field who want a surface level introduction to this technical area.

Of course I am not the authority on subject by any means but nevertheless I feel that there is something here to contribute. My question is mainly whether or not this could be used to my favour in future graduate admissions processes, or even academic applications beyond that? Assuming of course that I have written it at an acceptable level to the "real experts" who might read it.

EDIT: Just to clarify, I am in no way under the impression that this would replace legitimate academic work (hence in a CV this would go under "other interests",etc.) - indeed it should not. I am simply wondering whether it would be an added bonus (and if so, to what extent) that academia looks favourably upon.
The notion of authorship in wikipedia is rather antithetical to the notion of authorship in "standard" academic works.  Wikipedia articles don't have "bylines," and the point is that anyone in the world is welcome to make constructive edits and/or additions to an article at any time.  Even if you feel that you are the primary or sole author of an article at time t_1, at some time t_2 > t_1 this may no longer be true. Finally, the ethos of wikipedia is such that other wikipedians would not necessarily be happy to see a given person claiming "credit" in this way.  

If you are motivated to write such a wikipedia article, I suggest that you give it a go -- it has the potential to be both a learning experience for you and result in something of interest and use to many people.  However, if you want academic credit I suggest you write something more substantial, formal and/or independent.  As the head of a graduate admissions committee (albeit in mathematics, not physics) I would be more impressed even by a sequence of blog posts than by a wikipedia article.  Still probably not crucially impressed by the way, but more impressed.