I realize this, but the article doesn't provide any clear definition of what actually is a bad comment. It only gives trivial examples of bad comments such as "increment a by one".

Since I don't think anyone here would argue that "increment a by one" is a useful comment, the part about duplicate/obvious comments isn't adding much to the discussion about the usefulness of comments.

Nevertheless, it's true that comments cannot be checked by the compiler, and that's a more interesting point, I think.