Idea

I think the way Stack Exchange is handling its user comments is the best way from a user experience perspective. What Stack Exchange provides (and I am pretty sure every developer on this planet knows this) is a two-level comment functionality with a main comment on level 1 and any amount of sub comments to the given main comment on level 2. Level 0 is the question.

New Confluence feature

In Confluence, Level 0 is the Confluence page or blog post. Level 1 should be the main comment, level 1 the sub comments.
In addition, each confluence user should be able to sort the main comments by date decending or ascending. In this context please refer to CONF-2587. The sorting should have no effect on the sub comments.

For ascending sort order.
>PAGE OR BLOG POST
>> Main comment 1
>>> Sub comment 1.1
>>> Sub comment 1.2
>>> ...
>> Main comment 2
>>> Sub comment 2.1
>>> Sub comment 2.2
>>> ...
...

For descending sort order.
>PAGE OR BLOG POST
>> Main comment 2
>>> Sub comment 2.1
>>> Sub comment 2.2
>>> ...
>> Main comment 1
>>> Sub comment 1.1
>>> Sub comment 1.2
>>> ...
...