I was wondering if there's a friends list/guild list broker addon that is efficient and maintained and that also has that functionality to allow you to click someone in the tooltip to whisper them. Similar to Fubar_friendsfu and Fubar_guildfu, but obviously a broker addon. :)
Like the pico ones, StatBlock_Folks doesn't allow click-to-whisper (as Ara does). But it uses the least CPU time of any of them on idle.
Tested with the dependency-free tekBlocks LDB display:
Ara Broker Guild Friends: 0.340 to 0.380 CPU/sec.
picoFriends: 0.125-0.155 CPU/sec.
picoGuild: 0.100-0.120 CPU/sec.
StatBlock_Folks: 0.0 CPU/sec. And it doesn't change no matter how many people log on.