I'm intending this question to be a place for discussion about tag-wiki policies, which after the discussion can be included in What makes a good tag-wiki entry?. This way, that question can be kept clean and a bit FAQ-like. If you think this isn't the best discussion format, please make suggestions; I just didn't feel like asking a question on each single question was the right thing.
So here are some questions I have:
1. Markdown / backticks
I've seen some tag wiki excerpts that still contain backticks (`) to indicate code, e.g. titles, which imho doesn't look good, in particular considering that it's pretty clear what's code and what isn't. The same applies to question titles, and I think we discourage use of backticks in question titles. Hence:
Should backticks be used in tag wiki excerpts? I say: no.
2. Duplicate excerpt in "big" tag wiki?
Do an excerpt and the "big" tag wiki entry complement each other or are the independent from each other? I.e., should the "big" tag wiki reduplicate all the information given in the excerpt? If there's no "big" entry, should the excerpt just be copied there?
Since the "big" entry never appears on its own afaik, I don't think this is necessary. It happens frequently, though, e.g. in small-caps.
3. Taking package descriptions from ctan.org
When I started the titling tag wiki, I looked up http://www.ctan.org/pkg/titling and found a good and concise description of the package. Thus, I copied it and added "(quoted from http://www.ctan.org/pkg/titling)". Is this ok? I just figured "Why make up a new description if the package author, who probably knows the package best, has already provided such a great description?". etoolbox used the CTAN description as well and even used blockquote markup.