CensusPlusClassic

CensusPlusClassic is a fixed version of CensusPlus that works with Wow Classic. There is also a data aggregation website for merging and rendering all that data that you guys collect.

Check out: WowClassicPopulation.com

CensusPlusClassic is a mod which records details about the characters online in your faction at the time of the polling. This is done with liberal use of the in-game /who command via the Wholib. The information is then stored in the CensusPlus.lua in your account's SavedVariables folder, which you can be uploaded to websites like WowClassicPopulation.com. Sites like these sort the information and then display it on their site in chart and graph form.

UPDATE

After Blizzard added a protection to the SendWho() command Ceron257 came a around with some really nice workarounds to trigger /who requests manually.

Semi automatic who requests

To enable this feature install the latest version of the addon and then go into the CensusPlusClassic options; at the bottom of the settings page enable

• Send who request on mouse clicks in world
  Don't forget to do a /reload after this

After activating this settings who request will be triggered

• on mouse clicks in the 3D window (like turning the camera with mouse, interacting with things in the world, clicking players, loot mobs etc.)

Macro

You can also trigger manual /who requests from your most used macros or make one especially for this purpose.
Just do something like this:

#showtooltip
/run ManualWho()
/cast Mind Blast

Keybinding

In your ingame keybind settings you can also assign a key for issuing a manual /who request.