What happened with forum?

I don't understand, why this forum some time ago has become a bulk of spam? Posted messages don't appear, but spam posts multiply in progress.

I will remove the spam

I will remove the spam promptly if they got through the auto spam filter.

I have been having trouble

I have been having trouble posting some replies. I just discovered that one problem causing that is, as I routinely have on this forum for some, putting just a "period" character in the subject line now triggers the spam filter. I have been using this method to avoid a fragment of my first sentence being injected into the subject line automatically, if I leave the subject line blank. (I have found that to be an distracting feature when reading the threads, so have tried to avoid that.)