Just start scroll to the bottom of system logs - you will start see e-mails of users, some russian-texts with illegal services, porn link, drug links, and a lot more crazy stuff, lol
I start understand - if you will scroll much lower, you will see posts of users from 2003 - as i understand previously WM did have another website or so, for those users to chat. And this drugs advertisement is just how system copy those messages from that old website, now i understand why that happen (i may be wrong, lol)
At first I thought that might indeed be it, but I’m not sure if this is the case. If you look at this topic you can see time has passed between the posts. If those posts were copied I would expect the dates to be very close together.
The old SMF forum was imported so as to have all of the old contents available and indexed for searching, as some of it was still relevant and useful.
Unfortunately, this also imported the spam problem that smf forums had as well. Those posts appear as “system” sourced like the other old contents that had no user.