In a lot of countries whatsapp is the defacto IM, but I live in a country where facebook messenger and viber became the standard for some reason. I guess they measured how much citizen they can reach on each platform and selected messenger based on that data.

This is not for MEPs to message each other, not the recommendation by the Comission, this site is for ordinary citizens to get information. I think the biggest problem is why only facebook messenger?I would expect other similar platforms there, like whatsapp, viber, telegram or imessage.