What do you think Wenger means by an "organizational unit"?

Wenger states "These 'communities of practice' are mostly informal and distinct from organizational units"

Wenger describes the relationship between 'communities of practice' and organizational units! He states that "'Communities of practice' exist in any organisation" but what he means by this organizational unit is that the memberships of these 'communities if practice' are 'based on particpation rather than official status' Therefore it is to be understood that they are not bound by organizational affiliations.

I understand that these organizational units are most likely to be within a work/ business type situation. It is a unit in which people address each other on recurring problems. Therefore by participating in these 'Units' a communal memory can be formed and will help them to do their job without having to remember everything themselves!

With this idea in mind it is important to consider that these organizational units are made up of people who have to be together whereas people in a community of practice have chosen to be together.