Usability Yes. Social Features, Uh-Oh.

The recommendation currently proposes trying to create groups around categories. So, to try and find potential flashpoints I looked at category:abortion where you will find sub categories "pro-choice movement" and "pro-life movement".

So I can see the potential for groups to form around both those categories and start hurling rocks at each other. But we have WP:CIVIL, WP:NPOV, WP:3RR and I'm sure many other policies and punishments in place to deal with problems that may arise.

Essentially the aim of the recommendation is to grow the community and make them inclined to spend more time on the site. More people and more edits means more drama, more arguments... but also more recent changes patrollers, more admins (more arbs if necessary), more content.

If the community grows everything grows, good and bad.

But the fact is the software, as it stands, doesn't give users easy ways to interact with each other as a group. People bond in groups and like to keep up with people in that group. Anything we can do to facilitate groups will bring people back to the site.

But I'm repeating my arguments: I think either you're a group pessimist or a group optimist. Whilst recognising the dangers of groups I remain an optimist.

Actually, an idea has just occurred to me; the recommendation suggests that you effectively join "a category" (each category would have a 'join' function). So why not say that if any category becomes host to a troublesome group you simply switch off the functionality for that group? A sort of 'groups for deletion' style process?

I'll add something to the recommendation...