Popular chat limits?

Question

Social media

IT IS NOT NEEDED TO WRITE - ALL THIS IS ALLOWED FOR YOU, ETC.!!!
Max number of chat participants?
Vk=500?
Viber=250?
skype=300?
ACE=10000?
Telegram? (there the word chat itself is not mentioned at all in the documentation?)
classmates? (something is muddied with the messenger there there ... turn it on and off?)
Facebook? (is there a chat on fb at all?)
watsap? (Watsap client under windows only works if the client on the phone is turned on and has Internet access?)