Since the beginning of May Wargaming is sharing the amount of currently active players. This information is available for World of Tanks, World of Tanks Blitz and World of Warplanes.
World of Warships is officially not supported yet, but I got some hints over from wotapi.ru how to scrap is from Wargamings website. Additionally, I got the full data for World of Warships till today. Thanks!
vBAddict is collecting the server status each five minutes. Data of vBAddict is pulled directly from the database.
Link for an overview of currently active players:
Example details for World of Tanks:
wotapi.ru is also running their own data collector. Take a look
at their little different presentation of the same data.