Post History

Personal opinion, not speaking for the team:

I don't think we need a blanket ban on links, but we should make sure such links are actually necessary when used.  Sometimes a link to a product listing (whether the original manufacturer or a third-party vendor) is useful; often it is not.  It sounds like it wasn't needed in the case in question, and your inclination to edit was correct (or would have been if the author had not deleted the post).  

If the linked information is relevant context, then "here's a link that proves this price (as of this date)" is more useful than "I saw it listed for this price" -- think of it as a citation.  *Better* would be to archive that link and link to the archive, which is more durable and will still match the post a year from now, but I don't think we need to require, network-wide, that product links never be used.

Individual communities are welcome to set stricter policies, and the community can edit where the links don't add to the post or where archive links would be better.

Spam should be nuked from orbit, but links like what are described here aren't spam.  I think we need to evaluate individual cases.