Surrounding code by backticks is the only way to include code in comments. While everyone learns quickly how to do this, it is not so obvious how to include a backtick in code (please see that link).
In Mathematica, backticks are particularly common. As a result, on StackOverflow I regularly see people (even some regulars) writing ' as a workaround (see e.g. Mike's comment here), or simply incorrectly formatted comments.
If possible, on mathematica.stackexchange.com it should be explained at several more easily visible places (FAQ, main editor help or comment editor help) how to do this.
