Top "Spam-prevention" questions

Question context is related to spam prevention/filtering

Stop spam without captcha

I want to stop spammers from using my site. But I find CAPTCHA very annoying. I am not just talking …

captcha spam-prevention
How to stop spammers from getting the email address from a mailto link?

Duplicate: Best way to obfuscate an e-mail address on a website? Effective method to hide email from spam bots What …

javascript spam-prevention mailto
How effective is the honeypot technique against spam?

By "honeypot", I mean more or less this practice: #Register form <style> .hideme{ display:none; visibility: hidden; } </…

php spam spam-prevention honeypot
Spam Prevention/Reduction - Contact Form?

I want to add a simple Contact form to my web site so that customers can contact me easily. <…

javascript html spam-prevention
Prevent site data from being crawled and ripped

I'm looking into building a content site with possibly thousands of different entries, accessible by index and by search. What …

web-crawler spam-prevention
Nginx block from referrer

I need block all http connections, who have referrer click2dad.net. I write in mysite.conf: location / { valid_referers ~.*…

nginx spam-prevention referrer-spam
How does Google's reCAPTCHA v3 work?

Google has rolled out reCAPTCHA v3. It does away with all user the friction. I wish to use it to …

javascript recaptcha verification spam-prevention invisible-recaptcha
What is the difference between a SPF include: and a:?

I have read through the documentation but the difference is still not very clear to me. My understanding is: 1) include: …

email spam-prevention spf
Bypass Gmail's spam filter (mails sent with PHP from a shared host)

TL;DR: Mails sent from shared hosting (such as a cheap domain from Unoeuro or One.com) end up in …

php email spam swiftmailer spam-prevention
How to avoid marked as spam by Gmail on sending mass email?

I created event registration web sites (you can imagine something like http://www.eventbrite.com/), which allow users to subscribe …

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