WordPress 2.7 which is due for release any day now introduces the ability to have threaded conversations or, threaded comments. However, not every theme available for WordPress is going to have support for this new feature built in meaning you might have to add in the necessary changes yourself. No worries though as Sarah from BloggingTips.com has crafted an excellent post that walks you through from beginning to end on how to add this support to your theme.
Note that you do not HAVE to add this support to your theme. This feature/tutorial is only for those looking to use the threaded comment feature in WordPress 2.7 but who are using a theme which doesn’t support the new functionality.