The Stallion SEO Ad Theme includes titles for comments. You can see it in action in the comments below, there’s a form box with the comment called “Comment Title”).
I’ve taken the Hikari Titled Comments Plugin verbatim (made no changes to the code of the plugin) and packaged it with the Stallion theme files (it installs under the Stallion “Advanced SEO” options page). Had a very quick browse through the Hikari site (follow the link above) and looks like he might have a few WordPress plugin gems (the Hikari Titled Comments plugin was a nice find), will have to check them out when I find the time.
This Comment title (added by you or your visitors) not only gives each comment a title which you could edit for SEO reasons (add SEO’d comment titles to comments without a comment title for example), but the comment title is also used by another packaged SEO plugin called Stallion SEO Super Comments Plugin (I use a highly customised version of the SEO Super Comments plugin which only works with my themes) which produces pages from large comments when this plugin is activated.
See the comments below for examples of both plugins in action, there’s a link at the bottom of page comments to the counterpart Post like comment.
When both plugins are active (which takes three clicks of the mouse) the SEO Super Comments plugin comment pages will use the comment titles as the title of the pages, this gives you more control over the SEO of these extra pages and has the potential of increasing the traffic to your site through more long tail SERPs.