I'm still new here and a poster suggested I put a comment in the Wiki he created for his answer. How do I access the Wiki? Is it specific to chemistry?
For a quick intro to Community Wiki (and why we don't necessarily need to use it), see my answer on https://chemistry.meta.stackexchange.com/a/407.
Briefly, making an answer Community Wiki lowers the rep requirements to make an edit to that answer. It mainly serves to encourage collaboration at this point in its evolution. In this case, thomij was asking you to collaborate by adding your information directly into his answer. The system keeps track of who has edited an answer and what percentage was contributed by each user, so everyone gets "credit", but no one earns any reputation on it.
I would say that when the editing of answers is going to be limited to 2-3 users, and there's no antagonism going on (where there seems to be none in this case), it's best just to perform the edits without wikifying the answer, but I'll leave that up to thomij.
Community Wiki is not the same concept as the tag wikis, which I think is where the confusion arises. The tag wikis are meant to contain general information about the subject and how the tag is to be applied to questions. See https://chemistry.stackexchange.com/tags/organic-chemistry/info for a good example.