Reducing spam

As an administrator of CKAN, I don't want my public site to be polluted with spam. Nor do I want to re-invent the wheel and maintain something, that others are doing.

I would like something like [Mollom](http://mollom.com/) in Drupal, or [Akismet](http://akismet.com/) with Wordpress, or StopForumSpam with MediaWiki (and if I'm using one of those pieces of software already, on the same site), to integrate with the existing keys).

I don't believe captchas are useful, and make a very poor user experience.

I would like an extension that, once I've registered and got an API key, I can essentially install, update my config file with the secrets, and it just works.

I might also want to have an aging factor, where new users posting a lot (from an external address) in a short timescale suddenly get rate limited/blocked, until an admin unlocks them.

Compare the requested Mollom, Akismet, and StopForumSpam integrations, including API-key configuration and reuse of existing site credentials. Define the scope for external spam filtering separately from the proposed new-user aging, rate-limiting, and administrator-unlock behavior.

Written by the indexing model from the issue text.