This thread is the first result in Bing and Google searches when looking for "constant contact spf" and because it's so outdated it really needs taken down because it's now WRONG information. The first response in the thread recommends including ccsend.com but that isn't even mentioned in the knowledgebase article
The knowledgebase states to include constantcontact.com but nothing is said about ccsend. According to openspf.org, this would likely cause an SPF check against your domain to fail, but even if it didn't, it's highly recommended to not use too many 'include' mechanisms: "SPF implementations MUST limit the number of mechanisms and modifiers that do DNS lookups to at most 10 per SPF check, including any lookups caused by the use of the "include" mechanism or the "redirect" modifier" (http://www.openspf.org/RFC_4408#processing-limits)
Thank you for reaching out about this post coming up as the first result on your search. We don't have control over what posts will pull from searches in external tools, so we always recommend using the Knowledgebase directly, to make sure you're seeing the most up to date information. I apologize for any confusion this may have caused. It sounds like you were able to find the information you needed but we do have separate articles regarding self publishing and the Authentication option if you'd like to learn more. If you have additional questions, please reach out to our Account Review team directly, and they'll be more than happy to address any concerns!
Thanks for the reply, Amber. It's just that the interwebs are becoming very cluttered with bad (read: outdated) information so, in a way, you can control what appears in a search engine by removing this thread. Again, it's wrong information so why have it out there? The thread is 11 years old. I don't recall the last time I've read tech information from 11 years ago that's still relevant today.