What is the vBulletin Anti-Spam service key
 

Can anyone tell me what the vBulletin Anti-Spam service key code is
We are having spamming issues so I have gone through the settings in admin control under*VBulletin Options there is a*spam management setting group in there it askes for a*vBulletin Anti-Spam Key
this is exactly what is next to the key box where the key code has to be entered

"vBulletin Anti-Spam Key
Enter a vBulletin Anti-Spam service key to enable scanning of user data where supported"

Can you please tell me what this key is so I can enable the spam management.

Thanks in advance