The idea behind privacy mode is to have it permanently enabled, so that you get the stats, without displaying the actual logs on the web admin, so that people on your network couldn't just browse to the Admin page and look.
Another option is to put a password on the web admin.
This doesn't really work... when you have access to the settings and the allowed DNS queries, you also have access to the switch to disable "privacy mode".
All this switch does is hiding the allowed DNS queries from the persons who can also unhide them.
I think this feature needs to become really a privacy mode, or be renamed to prevent false expectations of privacy.
I think that's a fair shout. We're reworking things at the moment with the impending release of the FTL api, which should give us much more control over what we display.
Sorry to bring this old thread back to life but I thought it was best rather than create a new post.
I've enabled privacy mode which shows the client as hidden in the query log however I can still see which device made the request by navigating to Dashboard -> Top Clients and selecting a client from the list.
I still think it's nice to see which clients are making the most requests but if privacy mode is enabled I don't think it should let you see which clients are making those requests. I hope that makes sense.
Note: you should also disable the log file if you don't want queries logged to disk. FTLDNS will probably be released with file system logging disabled.