Comments added to an article are only accessible from the bottom of the HTML or Abstract pages. The PDF insterstitial page has no comment information/links (and I'm not entirely sure it should); and while there is a link to add new comments in the RT, if enabled (going to comment/add/n/n), there is no link to go directly to comments that have already been added (pointing to comment/view/n/n). This isn't so much of an issue when journals aren't open access and subsequently have a "Details" sub-page; but this isn't always the case, and comments are still hidden if a user is looking at the PDF directly. 

One possible solution is to link to comments directly from the ToC, to one side of the galley links. This would raise the comments' profile, too. Another possibility would be to include a 'view comments' link in the RT, or replace the current 'add comments' link with a general 'Comments' link whereby users would be able to do either. 

(Courtesy of http://pkp.sfu.ca/support/forum/viewtopic.php?f=2&t=3847&p=15785#p15785).