How do you configure MEDIA_ROOT and MEDIA_URL?

How do you configure MEDIA_ROOT and MEDIA_URL? This is mentioned in this answer and this doc, but no documentation is provided about how to actually set up these variables and configure your system appropriately. I tried googling and couldn't find anything.

Also, it seems like there is a setting ASKBOT_FILE_UPLOAD_DIR. Since avatars are user uploaded, can't they just be put in ASKBOT_FILE_UPLOAD_DIR, which makes configuration simpler?

You can set MEDIA_ROOT and MEDIA_URL to the same values as ASKBOT_FILE_UPLOAD_DIR and ASKBOT_UPLOADED_FILES_URL (now noticing that settings are named inconsistently.

Django Avatar app wants to use MEDIA_ROOT and the MEDIA_URL. Maybe askbot should use the same and create a subdirectory within and comply with the django's convention better.