Letitia A rumour can be round the world while the truth is still getting its boots on. This is what happened - Gransnet has a Faceboin a general way that are being discussed in the forums, have competitions, encourage people to join, and so on. They also have a Twitter account and post short things on that, (and, though I don't know whether they do this ot not, it is possible to link the FB and Twitter so that the first sentence or so of a Facebook post automatically gets tweeted - I repeat, I don't know whether they do that or not, but it makes sense for a big organisation to do it and save a bit of time)
A little while ago someone mentioned a specific thread on the FB page and included a link, which also went on Twitter, thjus sending people's usernames and posts more publicly than anyone wanted. There was such an outcry on the forum when people realised this that GN promised that they would take care not to do it again.
This DM thing is not connected. It is nothing to do with GN publicing things, it is the DM copying stuff from the forums and using it in their online newspaper.