The mailman is still working for me when it's set to yes... Not sure why it would work for some members but not for others.
Try this... Of coarse make sure your 'activate mailman' setting is set to 'yes', then clear your browser cache, then reload the site.
Note that the mailman shows up ONLY for private messages, not any other type of notification. If you don't have unread private messages he won't be there.
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