This plugin enables you to download all posts in a single thread.  Currently json, html, csv, and plain text are the supported formats.  JSON uses raw data.  HTML utilizes the post parser so all bb code is transformed to the HTML equivalent.  This plugin does use a template for the html download.  Due to some threads containing several posts only the most important fields are actually pulled.  We may enable a setting in the future that lets you set what fields you want to be available.

You do have an option to disable it in certain forums.  You also have the ability to restrict which usergroups can use this feature.