I suspect we will have to discuss tags and their usage on a regular basis. Let us do so here; I propose one answer per instance and discussion in the comments.
Note that you can link to tags using a shortcode. For instance,
[tag:context-free] becomes context-free.
Please help with tag descriptions! These are the text that shows up when you hover over a tag (excerpt) and when you click on "info" in this popup (full version). For tags without description, you can propose one by clicking on "help us edit this wiki" in the popup; in general, the tag info page will show edit buttons.
If you suggest tag wiki entries, please keep in mind that excerpt should be short; it is shown in the boxes that pop up when hovering over a tag (on the main site). Have a look at the tag list; there are only three short lines for every tag. Therefore, the excerpts need to be snappy and descriptive. The community mods have rejected some of my suggestions on the grounds of length; I guess we should keep them at about 150 characters. You are very welcome to elaborate in the main text, though!