Does anybody have any advice on an NCOER bullet relating to Wikipedia?

If you can verify that the actions were actually adopted and had some valid measurable impact then I don't see it as any different then having an article published by a professional journal, or a suggestion adopted by the Army for maintenance, safety or TTPs which would be valid bullets due to the impact. Just going into Wikipedia and correcting grammar, punctuation, or trivial stuff wouldn't be the same impact or take the same effort. I'd dig deep into that one to:
- verify input
- determine effect
- quantify effort
A hokey bullet is worse then no bullet.
I'm not very familiar with the inner workings of Wikipedia, but I remember not being able to use them as primary sources cited in research for term papers because of a "relatively high degree" of inaccuracy.

I wouldn't want Wikipedia to appear anywhere on my NCOER, nor would I recommend it for anyone else.
What rating do you believe that helps support? I would suggest this doesn't represent setting one's self apart.
It's true that there is a need to set oneself apart.
I'm confident that he first thought of many who read the post was WTF. Likely the same response at a board.
I did have a bullet comment for an SAMC page I created over a decade ago, but that had information that would help someone preparing for the board or seeking information on Audie Murphy.

Seems off. Sort of like saying he did a great job picking up trash in front of Walmart. Whats that got to do with anything?

I guess you could argue that its a decent way of correctly representing the military to those who don't serve, or for those looking to enlist/commission. Even if its not an academically citable source misinformation on Wikipedia can skew or taint a civilian's perspective on the military.

Is it part of the ratee's job description?

A while back there was a social media page for military members where we could offer advice, knowledge and experiences with the young NCO's and troops, for the life of me I can't remember the site but its gone these days, I believe CSM Dan Elder was the NCOIC for it. I was a regular contributor with far less sarcasm and assholery that I use on RP and it was a bullet on my NCOER along with extra off duty activities relating to the different sections on an NOCER (Civil Air Patrol etc). While I can see raters and senior raters showing the whole NCO by including additional hour spent helping others, I would question using Wikipedia editing as the site can be edited constantly with both good and false info, so its like bailing out a sinking boat with a sponge. Social media both good and bad will become more and more included on evaluations and I think mostly for bad reasons. If I were reviewing and NCOER for corrections I would sit down with this NCO and ask a few questions about this and maybe offer him/her some better ideas to include on a document that can effect ones career and promotions. Promotion boards are pretty good and sifting through questionable bullets in NCOERS and having good laugh at some.

Hard to disagree or agree with that. The Smithsonian has a team devoted to correcting Wikipedia.