Enabling Comments

Worth thinking about why this exists at all. It is because Adobe like selling Acrobat, but by enabling for comments, they could instead sell the enabling software. So clearly this is not going to be free, hence it won't be in Reader. That said, recent versions of Reader can add some kinds of comments without enabling. Was it ever in Standard? I doubt it, this is the sort of thing for which Adobe like to sell Pro.

If you're uncertain, please describe the exact types of comment you want to enable.