For unordered lists (bullet points), there should be default indentation levels.

The mailing list is limited to 72 columns, so no horizontal space should be wasted.
Listify! should therefore default to indent level 0 (subtracting if necessary)

DokuWiki begins bullet point lists at two spaces (indent level 1).
Wikify! should therefore default to indent level 1 (adding 1 if necessary)