I am trying to make (and understand!) column groups for html export
According to http://orgmode.org/manual/Column-groups.html having a line
starting / and then showing < for group start and group end makes column
groups.

When I make and org file containing these 4 lines:

* head
  | /         | <                 > |     | < > |
  | some text | and some more       | d e | fg  |
  |           |                     |     |     |

all that happens on export is that the / < > etc literally appear in the
export!

Is there something else I should study?

Org-mode version 7.8.02