Having a WordPress site is great and very easy to maintain, but when it comes to comment spam it's a disaster... Luckily, there are few ways to reduce the spam almost to zero, using few useful plugins and some simple tricks.
Before installing any plugin to stop WordPress comment spam, it is mandatory to check the Discussion Settings. To access it, log in WordPress Admin Panel and go to Settings - Discussion. Here you can find some simple options about how WordPress should threat your comments from articles.
Note that the settings below will not stop WordPress comment spam completely, but it will reduce the number significantly. So, make sure to disable the first 2 options from default article settings which are:
You really don't need to notify anyone if you post their link on your website and moreover you don't need at all to be notified by anyone if they post your link to their website. Just to know, most of the pingbacks and trackbacks are coming from robots and spam bots, so if you want to reduce WordPress comment spam get rid of these 2 useless things.
Once these two are disabled you can go ahead with the others. Make sure to always moderate manually all comments, because spammy links/texts can hurt your website's rank in search engines.
As WordPress doesn't have a feature to NOT accept comments if they contain bad keywords (same thing like a validation), there is only available the comment blacklist which will only mark comments as spam if they contain the keywords you set.
If you still receive spam comments, check that comment and select few keywords from it and add them to blacklist. You will now receive emails only from authentic users who really needs your help. In this way, all spam comments will go to Spam Folder and you can easily delete all messages by using Empty Spam button and you don't even need to read team because they already contain the words added in the blacklist.
I ended up using a very simple captcha plugin without images, only text with random simple math operations. You can see it at the end of this post in action. In this way robots or bots can't guess the result that fast.
So, this simple captcha combined with another plugin which I use, named iThemes Security I still receive only one spam comment in 2 days. This one is a powerful plugin which can break your website if you don't use it correctly. Just make sure to go to settings and scroll down until you find WordPress Tweaks and check the following options only:
There are other security related options in this plugin, but use it with caution. Make sure to backup your database and files first if you decide to test the plugin.
WordPress might be vulnerable to security and spam comments, but if you use it wisely and know what tweaks to do, you can really enjoy it. I love WordPress because of it's simplicity and friendly user interface. Let me know if my articles was helpful and come back with a comment of how much your WordPress comment spam was reduced.