The software I use allows me to set how many comments are displayed on an information page before it goes to a second page.
As a user I like having comments all on one page as it allows me to easily scroll down and read the threads I want.
From a search engine point of view Google may not like it as much since the page can get long and my keyword density starts to go through the roof as people comment on the topic (from the comment title and the content of the comment).
How many comments do most people allow on a page (currently mine is set to 50)?
Also the additional comment pages redisplays the original content of the page (with a canonical link back to the first page). Should I redisplay this information (it can be helpful to the user to see what the material that the comment is on)?
I think the key is not to allow the text in your comment area overwhelm the actual content your wrote. Depending on how big that content area usually is, you may find that 10 is best, or 30. It's a judgment call.
I don't think a canonical link for extra pages would do you much good, unless you don't want those pages in the index. That might be a good choice, however, depending on how useful the comments actually are. Again, it's a judgment call for your specific site with no absolute rules.
Yeah I have seen the ajax use as well. That is a little out of my league at the moment to do.
The content area is usually fairly large. For the user to reach the comments they must scroll down a page or 2.
The comments do not drown out my original content as they are at the bottom of the page. The reason I have the canonical link is that I didn't want a duplicate content issue on my original content if there are more than one page displayed (due to a lot of comments).
The canonical link doesn't help though with the comments since they are not duplicated content.
I think I may reduce the comments per page to 30 and remove my original content from displaying on any page except for the first page. If the user wants to see the original information they will have to go back to the first page.
The comments do not drown out my original content as they are at the bottom of the page.
If your original content is 10% of the page compared to comments taking up 90% of the page, I don't think having the content at the top will matter that much- it's still only 10% of the page's content.