In the past I and others have experienced some problems with the way that More Privacy Options for WPMu interacts with BuddyPress – or, to be more exact, with the way that the two don’t recognize each other. Blogs marked as private via MPO were getting plastered all over the public activity streams. In the past I have suggested some unpleasant but more or less functional core hacks, but now I’ve developed a plugin that does the job in the right way. It’s called … drumroll … BP MPO Activity Filter.