Several months ago I noticed that ChatGPT could reproduce and generate content from Reddit but not from Mumsnet. More recently it seems to be able to generate content from Mumsnet. For example, if I say "Can you find examples of parents discussing school X online?" or "Can you summarise all posts from Mumsnet user Y on topic Z?" then it will happily do it.
When was this change made, and how was it communicated to users?