Hikari Titled Comments enables each comment to have a title, so that commentators can give a subject meaning to their comments.
Unfortunately no. The only action hook that WordPress offers as default for themes to have in comments is 'comment_form', that normally is added below the comment textarea, it doesn't offer enough flexibility. And also there is no way for a plugin to include title to comments.
In reality, it could be done, but these 2 elements would hardly fit to themes layouts, you'd have a lot of trouble styling them, so it's much easier to just edit the theme.
You can, but you'll have to create that function. If you're using the default code, your comments are already simple, so just search the Web for a tutorial teaching how to create it. Then you'll be able to add title to your site comments :)
I'd love to be able to help, but it would require a few hours examining the theme, and even more time if its comment code is very different from standard, or some work if it uses WordPress default comment code.
Many themes also have damn ugly code that is pratically unreadable (if you've never read themes codes, believe me, I've already used a theme that was pretty looking in the browser but its code almost made me suicide its author!).
Unfortunately I don't have the time to do it. You of course can contact me if you find a bug or have any trouble that may involve my plugin code, but please don't ask me for themes support.
Yes, just go to Edit Comment Admin Page.
Go to the admin page where you see a list of your site comments and click the edit option (not the quick edit!) for the comment you wanna edit. In the page that will open, below the comment textarea there will be a box with an input text containing its current title (or empty if the comment has no title). Edit it as you want and save the comment :)
Sure, go to my plugin's home page and add comments saying what you think about having titles in comments :)
When a registered user edits an existing comment's title, wpnonce is used against the plugin filename AND this comment ID, so WordPress controls security regarding somebody trying to force a comment title change. A user also must have permission to edit a post to edit its comments' titles.
For a new comment being created, I've used no special security measure. If a user or visitor is allowed to create a comment, he is allowed to give it a title too. I let WordPress manage permissions to add new comments, if it's not allowed WordPress will simply not trigger the action that Hikari Titled Comments plugin uses to create the title. There are also spam protection plugins that deal with permissions to add comments.
Now, regarding what a user can use in a title (add a link to it for exemple), I've used the filter
wp_filter_kses() to control it, it's the same filter used in the comment body. In the same way WordPress works, if a user has 'unfiltered_html' permission, his comment body and title are not filtered, and if he doesn't have this permission the filter is used.
And if you also use the Hikari Email & URL Obfuscator plugin, it will obfuscate any link that may exist in a title :)
With these measures, I belive comment title is dealt in a similar way comment body is, I don't believe comment title must or should have deeper control than comment body. But if you think it should be done differently, just add a comment, with title ;) , to the plugin homepage with your ideas and concerns :)