But I realised that the last statistics on the various number of post per month stopped on November 2017, any reason why?
As a matter of (apparent) fact, part of the forum stats were disabled on or around 2017-12-13 (last reading).
This thread from that precise date depicts a seemingly DDoS attack on the forum on that day, leading to some features on the forum
being disabled. Part of the Forum Stats (not all, just those in the table "Forum History" of the Forum Stats) seem down since then.
Also the most users online are brand new member's with no post is that normal?
Yes ... old post of mine:
<...>
I wonder how many of those accounts haven’t even made a single post <...>
As to the number of accounts themselves, I haven’t got any recent data, but
in July 2018, 72% of the accounts were brand new, meaning bot created, nuked, or simply created without posts. That fact is important to understand when we discuss the number of created accounts on the forum (active accounts are therefore way less).