If you visit the AirNav forum, as I do regularly for a laugh, you may have noticed the vast amount of spam posts, often porn related. This can be embrassing if someone passes the computer whan checking the forum.
Spam posts have been apearing for months, often left undeleted for days. Clearly AirNav doesn't bother moderating the forum on a regular basis.
Then a few days ago it was suddenly spam free and I noticed a footer reference "SMF Spam blocked by CleanTalk".
From experience, the best way to avoid spam is to vet all new members and check their spam credentials.
Unfortunately for AirNav, CleanTalk is not the answer.

And 4 hours later, the post is still there.