This is a long post, so I’ll jump directly to the main topic. I’ve run a face to face comparison for 4 existing commenting systems: Disqus, IntenseDebate, JS-Kit and SezWho. The rest of the post presents the criteria I’ve used, the winners and references to specific features.
Please feel free to comment and correct me if I got anything wrong!
- User related Features
- Comment threading
- Anonymous posts
- Comment ranking and additional features (sort, most, filter, etc.)
- Rich format comments
- Owner related features:
- Spam filtering
- Comment moderation
- Search Engine Friendliness
- HTML/CSS customization
- Data access
- Programming API
- Data export
After completing the evaluation of the mentioned criteria, I have decided that there should be 2 categories: Blogs and Custom sites. Even if there are no immediate visible differences, the existence of a programming API offers a lot more extensibility and freedom to site owners, while this feature might not be as important as features like additional comment ranking features (sorting, filtering, recommendations, etc.) for blog owners.
Drum roll… The winners are:
- Winner: IntenseDebate
- Runner-up: Disqus
- Winner: Disqus
- Runner-up: IntenseDebate
|Anonymous Comments:||Y||Y||Y||Y |
|Comment ranking functionality||- ||Y||Y||Y|
|Rich format comments||Y||Y||Y||Y|
|Spam filtering:||Custom + Akismet ||Custom ||Akismet||Akismet |
(web + email)
(web + email)
(web + email)
|Search Engine Friendliness||Y ||N ||Y ||N |
|Widget (JS API):||Y||Y||Y||Y|
|Programming API:||Y||N ||N||N |
|Costs||Free||Free||Free for 25k pageviews
Low Traffic Forum
|GetSatisfaction||Q&A Forum ||FAQ Page |
Comment ranking functionality
Basically, once comments can be rated themselves, there is a lot of new functionality that can be offered by these services. I am thinking of: filtering the comment thread, sorting, most commented content, etc.
 I couldn’t find anything about Disqus support for additional functionality.
-  According to the following links, Disqus is employing a combination of custom filtering and Akismet integration
-  I couldn’t find any place in the IntenseDebate documentation detailing what solution is used, so I’ve concluded that some custom filtering is employed. Considering that IntenseDebate is now part of the WordPress universe, it might be possible to also integrate with Akismet.
- JS-Kit documentation is clear about this point: LINK
-  While some sources are mentioning the integration with Akismet for spam filtering, I couldn’t find this info in the SezWho documentation
All 3 Disqus, IntenseDebate and JS-Kit support advanced moderation features. But my advice would be to effectively test them if comment moderation is important for your site or blog.
 Unfortunately, I couldn’t find any info about SezWho’s support for comment moderation.
Search Engine Friendliness
This is probably the most debatable criterion used for evaluating the 4 services and unfortunately to cover it I will need a whole new post (which will come later on).
-  Disqus is offering a hosted page for each comment thread, so search engines can index the comments.
-  I’ve read about improvements implemented by IntenseDebate, but unfortunately these are not useful for the sites that do not use the IntenseDebate custom plugin
-  JS-Kit employs the same solution as Disqus.
-  No information available.
Disqus and JS-Kit approach to this problem is quite good (even if a bit complex) as with the help of some subdomain mapping you can instruct the search engines to see the comment thread content as site’s content.
-  I am still investigating the possibility to access IntenseDebate data through a programming API (see thread)
-  Even if there are a couple of sources mentioning a SezWho API (see Mashable and CenterNetworks I couldn’t find any reference to it in SezWho’s documentation
-  SezWho:
The basic SezWho rating, reputation and profile services are provided for free on the currently supported platforms. SezWho will be offering upgrades to premium products and services in the future, but basic SezWho integration for standard social media platforms will always be available as a free service.
-  JS-Kit Q&A Forum is unfortunately pretty unusable as there is no way to perform any searches. It has over 450 pages of comments, so even if I am pretty sure there is a lot of information in there, it is a pity that you cannot get to it. Search Engine Friendliness is a major and extremely important feature that you should consider while integrating a 3rd party commenting system.
-  SezWho FAQ Page contains minimal information and unfortunately I couldn’t find other sources.
Here is a set of other features compared on RWW:
SezWho documentation is pretty scarce, so I haven’t been able to find detailed information on the evaluated set of features.