Each can be toggled by clicking on the LDB display. The tooltip lists the click- and key-combinations to do so. Simple and no-frills. Only notifies you, no polite whisper. Uses about 15KiB of memory for me.
I wrote this to replace the blocking functionality of LeaveMeAlone for a ~95% memory usage savings and getting rid of FubarPlugin-2.0.
In order to use this addon you'll need a LibDataBroker display like Fortress or ButtonBin.
3.0.2-1b -> 3.0.3-1a
* Will not process party invites or trade requests from friends or guildies
From frayol's suggestions:
* Fixed Duel-blocking - thanks for pointing out the missing RegisterEvent, frayol, was already fixed in my local copy
* Changed wording on tooltip to used colored "Blocked" or "Unblocked"
TODO: Allow trade invites, etc. from party members