My bad! you're right, it's backticks
decklist in here
If you put something in `single backticks` you get a neat little inline block
The markup language being used for formatting posts is actually markdown, there's an overview here http://commonmark.org/help/ it's super easy to use once you're used to it.
so actually tags can be made by any user on the fly, they're open text fields, you should be able to edit the initial post in the thread and change the tags to whatever you want, though obviously if there's an existing tag you should tend toward using those, and I/the mod staff will go around cleaning up non-useful tags
If you have any trouble figuring it out, let me know