Over at SpamResource Al talks about how sharing content is like sharing needles.
If you’re going to share email templates with somebody else, you’re sharing in their reputation. Lots of good spam filters, like those at Cloudmark, Brightmail, Yahoo and elsewhere, they use what is commonly called “content fingerprinting.”
Content fingerprinting is something that a lot of people don’t talk about. However, it is the logical next step to deal with spammers who spend a lot of time attempting to work around IP based reputation. It is also why a number of senders with good reputation can see random poor delivery.
The moral of the story is be careful of who you allow to advertise in or generate content for your newsletters. Otherwise, you may see your delivery suffer.