Don't forget merit played a huge part in this. Lets give it sometime lets not jump into conclusions. Some of those new first timers on meta are actually looking for merit and from this post
He said i post or comment some ideas on Meta section because people who gave merits are here and i will most probably get one if i post here.
The title of that topic was "Post in Meta Section They Say, You will have merits they say" so that's how most of them are thinking and possibly when they get the merit they were searching for off to the alternative currency board or bitcoin discussion board to continue their spamming just to earn post count.
Anyway, their presence have added more creative suggestion and disscussion to the board. So lets just hope it last.