Right now the admin has to go to a screen and edit the user in order to add them to a group. Two drawbacks to this are 1) there's no clear mechanism for a user to request membership to a group and 2) it's rather tedious.

I propose a mechanism whereby a user can request access to a group. This doesn't require revealing the list of groups. An admin could set which groups are self-selectable (perhaps a flag on the group). When a user requests to be in the group, the admin receives an e-mail with Approve and Deny links.

Going further, there could be another flag to make the group free to join. This might be useful later for team management in unauthoritarian open-source projects.