in Acrobat or Reader with enabled commenting there is available menu item allowing to display Comments list with posibility to jump to any comment or to the next or previous one.
It would be nice to have such list - with limited functionality (read only) - also in Reader without enabled commenting. There are situations when commenting is only for information. At present the whole document must be scrolled down in Reader and checked page by page if there are comments. Using list and back/next buttons it would be much easier.