Hello,

A CMS-based site I manage is suffering from a small but ominously growing number of almost certainly bot-emplaced, invisible spam links placed in registered-user-only shoutboxes and user forums. "Link Spam", yes?

Until recently, I've kept my eyes on narrow tech issues, and I'm having trouble understanding what's going on. I understand that we need to tighten up our registration procedures, but more generally...

Do I understand correctly that our primary interest in combatting link spam on our site is that major search engines reduce or zero the search visibility of sites that contain link spam? Although we're non-commercial, we don't want to be at the bottom of the rankings, or eliminated altogether.

Are the linked-to sites the direct beneficiaries of the spam links, or is there some kind of indirection? What is the likely relationship between the link-spammers and the owners of the (directly or indirectly) linked-to sites? Are the owners of the linked-to sites paying the link-spammers for higher visibility? Are the owners aware that this method is being used?

It is my impression that major search engines are capable these days of detecting that given sites are being promoted by link spam, and that these sites may consequently be reduced in search rank or dropped altogether.

Do these sanctions occur frequently? Is there any potential value in sending notifications to the owners of the linked-to sites that their visibility is at risk?

TIA,

hen3ry