BuddyPress.org

The easiest would be for you to create multiple profile fields (job 1, job 2…) and prompt users to leave blank if not appropriate.

Another approach is to use a text area (one job per line), and then customise the output of this particular field to display how you wanted it to.

xprofile wasn’t built with the idea of letting *users* (vs admins) creating new profile fields. I think trying to do this would be full of difficulty so I’d recommend against it.