How smart is using Mollom?

We use both Mollom and StopForumSpam. That's in addition to a captcha on account sign up and blocking disposable email domains. This is the only way this forum is usable. A site as large and popular as this is a constant target of spam runs. Automated tools make signing up and posting via Drupal simple. And any captchas that can't be solved automatically are farmed out to underprivileged areas where people are paid a fraction of a cent to solve them. Third party utilities allow multiple sites to contribute to blacklists of IP addresses, email addresses, domains mentioned in comments, etc. Without all these checks, spam rates easily hit hundreds an hour.