reCAPTCHA is a CAPTCHA system that enables web hosts to distinguish between human and automated access to websites. The latest version aims to have as little user interaction as possible, using machine learning to analyse a user's actions and determine if they are a bot, and...
- - reCAPTCHA is the most popular Web-based alternative to Sblam!.
- - reCAPTCHA is the most popular free alternative to Sblam!.
hCaptcha is designed to solve the most labor intensive problem in machine learning: labeling massive amounts of data in a timely, affordable, and reliable way.
mosparo is the modern solution for protecting your online forms from spam. The protection method is quite simple: mosparo blocks spam using rules matching the form’s data. The detection method is comparable to an e-mail spam filter.
- - mosparo is the most popular Self-Hosted alternative to Sblam!.
- - mosparo is the most popular Open Source alternative to Sblam!.
A negative captcha has the exact same purpose as your run-of-the-mill image captcha: To keep bots from submitting forms. Image ("positive") captchas do this by implementing a step which only humans can do, but bots cannot: read jumbled characters from an image.
Negative Captcha FeaturesDiscontinued
The last update is from 2018.
Your favorite and most trusted "one stop shop" for the prevention of forum & blog spam, trusted by over 200,000 forums...
It allows you to filter and search for spammer comments on your channel and other's channel(s) in many different ways AND delete/report them all at once (see features below).
- - YouTube Spammer Purge is the most popular Windows, Mac & Linux alternative to Sblam!.
Say Goodbye to comment spam on your WordPress blog or website. Antispam Bee blocks spam comments and trackbacks effectively, without captchas and without sending personal information to third party services. It is free of charge, ad-free and 100% GDPR compliant.
Anti-Spam Features. CleanTalk protects your website from spam bots and spam in Comments, Orders, Widgets, Registrations, Bookings, And any custom web form, Contact Emails, Subscriptions, Checks the existing comments and users for spam.
Akismet checks your comments and contact form submissions against our global database of spam to prevent your site from publishing malicious content. You can review the comment spam it catches on your blog’s “Comments” admin screen.
Mollom is a freemium web service to get rid of spam, unwanted content and fake users on your Drupal, Wordpress and Joomla site or blog.Discontinued
"The Mollom content moderation service is no longer available … as of 2 April 2018."
Anti-spam plugin blocks automatic spam in comments section. No captcha. Plugin is easy to use: just install it and it just works. Blocked comments can be stored in the Spam area if needed. This can be enabled/disabled via Settings page.