It appears that a glitch means some people’s private messages or chats are now visable on their timelines. Still to be confirmed or denied by FB.
How to fix it:
Click on a year on your the timeline.
You will see an item saying ‘xx friends posted on your timeline’
This appears to have been newly updated, and is where some people are saying messages are going. You can click on the small pencil icon (Edit or Remove) and press “Hide from Timeline” – you’ll need to repeat this for every year individually.
Apparently for some users messages have now been disabled.
The only way for your privacy to be absolutely safe is for data not to be retained at all. Facebook’s attitude has often been to hold onto as much data as possible for as long as possible, and this highlights the risks of that. Apologies may not be enough for people who have now had details of intimate conversations revealed to their friends.
It also demonstrates how acutely difficult it is to ever guarantee data security, and at a time the British Government is considering asking companies to collect even more data about their customers, emphasises the real dangers this poses even with corporate security operations.