I've been a member of SEOConsultants for several years and have always been impressed with the way Edward runs the show over there. So when he sends email and asks folks to post about an issue he feels important -- I'm happy to do it. From Edward:
DNS Recursion is DNS Cache Poisoning
This issue has now escalated to a much higher level as we have some topics going on at WebmasterWorld that have discovered particular instances of DNS Cache Poisoning and how it is affecting those involved.
As a search marketer, it is your responsibility to understand at least the basics of what is happening so that you can report your findings to those reponsible for your DNS, Web Hosting, Email, etc.
Please, this is a very serious issue and we hope that those of you with Blogs, Forums, etc. will help get the word out there so that the server administrators of this world can help close the gap that shows 75% of DNS Servers are open for recursion. That is a scary thought!