IntenseDebate comments enhance and encourage conversation on your blog or website

IntenseDebate comments enhance and encourage conversation on your blog or website:

Another commenting system 

"Supercharge your community
Fire up the debate with commenter profiles, reputation scores, and OpenID. With IntenseDebate you'll tap into a whole new network of sites with avid bloggers and commenters. And that's just the tip of the iceberg!"

Gravatar - Globally Recognized Avatars

Gravatar - Globally Recognized Avatars

A gravatar, or globally recognized avatar, is quite simply an image that follows you from site to site appearing beside your name when you do things. Avatars help identify your posts on blogs and web forums, so why not on any site?

                    

Stay up to date with The Gravatar blog

How do I get a gravatar?

Signing up for a gravatar.com account is FREE, and all that's required is your email address. Once you've signed up you can upload your avatar image and soon after you'll start seeing it on gravatar enabled sites!

DISQUS | Turn Blog Comments into a Webwide Discussion with a Powerful Comment System

DISQUS | Turn Blog Comments into a Webwide Discussion with a Powerful Comment System: "Disqus is a powerful comment system that easily enhances the discussion on websites.

In minutes, connect your community with those of thousands of other websites.

Track conversations across the web, plus bridge discussions with your favorite services such as FriendFeed and Plaxo."

This system is popular and seems to be well recommended. It also has an API

What is Get Satisfaction?

What is Get Satisfaction?: "Get Satisfaction is a community that helps people to get the most from the products they use, and where companies are encouraged to get real with their customers." 

Google Groups

Google Groups: "Choose an Access level
Public - Anyone can read the archives. Anyone can join, but only members can post messages, view the members list, create pages and upload files.

  Announcement-only - Anyone can read the archives. Anyone can join, but only managers can post messages, view the members list, create pages and upload files.

Restricted - People must be invited to join the group. Only members can post messages, read the archives, view the members list, create pages and upload files. Your group and its archives do not appear in public Google search results or the directory."