I don't always tout the quality of a service and further more it is much less likely I will pay for a service if I can get it for FREE or cheaper. But I am doing both of that with this service.
CleanTalk: Anti-Spam for Websites is a service for your website that nearly eliminates all spam that you get and see.
I have been using a number of different modules for Drupal for years tying in different services to limit spam. Some of these you may of hear of and most likely you have been presented with them on a website that you have visited. You know the ones where you have to spell something out or do a math problem or maybe select certain squares with certain images.
I've seen them all and have tried most of them on this site or other sites that I have created. Though some are better than others, most still let some spam through and at minimum, they are a pain in the a$$ for the users who have to answer the questions, sometimes frustrating them so much, that they just leave.
Then I heard about CleanTalk while I was redesigning this site. They have modules and plugins for most of the major CMS's and have a API if you want to connect into them. I decided to try them out for a week as they offer this for you so you can try their service. And boy was I impressed. It blocked about 75 spam requests that week.
Now you may be thinking, it's blocking all of your visitors or stopping them from accessing content. This cant be further from the truth. I've still been getting contact emails, comments have still been posted on the site. But if those things were true, CleanTalk provides an awesome dashboard where you can see what has been blocked, who, countries, amongst many other things.
I have now proceeded to install this on a number of other sites and to remove the draconian services that were installed. CleanTalk costs about $25USD per-year for the service but I think it is well worth the cost and the hassle free spam protection that you will have for your sites.