Простой способ борьбы с спамом в комментария? , при помощи общедоступного и бесплатного сервиса от компании Яндекс Чистый Веб. Минимум настроек, максимум результата.. A simple way of dealing with comment spam, using publicly available and free service from the company Yandex Net Web. Minimum settings, the best of it..

Spam Oborona YandexCleanWeb

The fight against spam in comments by free service Yandex .NET Web

Denis V (Artprima)

AP HoneyPot WordPress Plugin, based on Jan Stępień’s http:BL, allows you 
to verify IP addresses of clients connecting to your blog against the Project 
Honey Pot database. Thanks to http:BL API you can quickly check whether your 
visitor is an email harvester, a comment spammer or any other malicious 
creature. Communication with verification server is done via DNS request 
mechanism, which makes the query and response even quicker. Now, thanks 
to AP HoneyPot WordPress Plugin any potentially harmful clients are denied 
from accessing your blog and therefore abusing it.
<h4>Your Feedback Matters</h4>
Bugs to report? Feature requests? Criticism? New ideas? We want to hear from 
you! Do not hesitate. Get in touch with us and share your views.

AP HoneyPot WordPress Plugin

Hard to believe I've been using this fro over 3 years, and the previous one before for even longer. No I wonder this is still being maintained, but still using in the meantime. 

Updated 3 years ago and still works great

AP HoneyPot WordPress Plugin allows you to verify IP addresses of clients connecting to your blog against the Project Honey Pot database.

Spam Oborona YandexCleanWeb vs AP HoneyPot WordPress Plugin