Avoid handling sensitive information such as anonymous tips and personal data in the message functions of social media platforms (such as Direct Messaging or DM, Twitter and Facebook Messenger). Some message services are encrypted (WhatsApp is, but not Messenger) and are thus more secure. But you should still avoid mentioning sensitive information or contact with anonymous sources on social media. More detailed information about source protection on the internet can be found in the Internet Foundation in Sweden’s Handbok i digitalt källskydd (in Swedish only – handbook on digital source protection) by Sus Andersson, Fredrik Laurin and Petra Jankov.
Also be aware that many platforms are subject to the laws of other countries, which can mean that privacy protection for messages is weaker. There are examples of information having been provided to the police and government agencies from both Twitter and Facebook.