Nibirumail is totally against spam, this being one of the reasons why we started this service. To fight spam, we adopt multiple strategies developerd by our tech partners such as Lenus Lab, Akismet and many others.
We do not trust in CAPTCHA method because pur services want to be always easy-to-use,. easy-to-install, easy-to-distribute among any kind of users of any ages and any skills.
Actually we are able to block the 99% of authomatic SPAM submissions* without using Captcha technologies. We are very proud of that.
* internal research.