Are there any often mentioned products or services for adding end user comments to pages that aren't served up by a CMS or blog engine? Assuming the host can execute PHP, Python, ASP.NET classic, or other very common programming languages.
The solution must:
Allow end users to leave a comment on a web page, with an easy login process for the user.
Have very robust anti-spam capabilities, preferably with some sort of heuristics and crowd-sourced blacklists (like Akismet).
Have an administration backend with spam management and batch approve capabilities.
This is related to but still different from "Adding comments to static pages?". There is also the more recent "Facebook comment and other commenting system for SEO".