The most effective way to prevent comment spam is to automatically identify and intercept it through programmatic means. 1. Use verification code mechanisms (such as Google reCAPTCHA or hCaptcha) to effectively distinguish humans from robots, especially suitable for public websites; 2. Set hidden fields (Honeypot technology), and use robots to automatically fill in features to identify spam comments without affecting user experience; 3. Check the blacklist of comment content keywords, filter spam information through sensitive word matching, and pay attention to avoid misjudgment; 4. Judge comment frequency and source IP, limit the number of submissions per unit time and establish a blacklist; 5. Use third-party anti-spam services (such as Akismet, Cloudflare) to improve identification accuracy. Two or three methods can be selected to combine them according to the actual situation of the website, with the focus on pre-interception rather than post-cleaning.

One of the most effective ways to prevent comment spam is to automatically identify and intercept it through programmatic means. Although it is almost impossible to completely eliminate the rules and mechanisms, reasonable setting of rules and mechanisms can greatly reduce the pressure of manual review.

1. Use the verification code mechanism (CAPTCHA)

Verification codes are one of the most common ways to prevent spam, especially for public-facing websites or blogs.

• Google reCAPTCHA is the most widely used one at present. It not only verifies whether the user is a human, but also determines whether it is suspicious through behavioral analysis.
• You can choose to trigger the verification code when submitting a comment instead of displaying it on all pages, which has less impact on the user experience.
• Note: Mobile users may have poor experience with traditional image verification codes, and it is recommended to use alternatives such as "unsensible" reCAPTCHA v3 or hCaptcha.

2. Set hidden fields (Honeypot technology)

Many robots will automatically fill in all input boxes in the form, including those that cannot be seen by the naked eye.

• Add a hidden field (such as named website or url ) to the comment form, which normal users will not fill in, while garbage bots will usually fill in the link.
• Check whether the field has content when submitting, and if so, it will be determined as spam.
• This method does not require user interaction and has no impact on user experience. It is suitable for use in combination with other mechanisms.

3. Check the comment content keyword blacklist

Many spam comments include specific keywords, such as “buy now,” “viagra,” “click here,” etc.

• Maintain a list of sensitive words and perform match checks when the backend receives comments.
• If the keyword is hit, it can be rejected directly or marked as pending review.
• Misjudgment issues need to be paid attention to, such as the word “free” may be normal in some contexts.

4. Determine the frequency of comments and source IP

Automated scripts tend to submit comments in large quantities in a short period of time, which can be identified by frequency control.

• Limit the number of comments per unit time for the same IP address, such as up to 5 comments per minute.
• Record IP addresses that frequently send spam comments and create your own blacklist.
• You can cooperate with third-party services (such as Akismet and Cloudflare) for more in-depth analysis and filtering.

5. Use third-party anti-spam services

If you don't want to start from scratch, consider integrating existing anti-spam services:

• Akismet : Officially recommended plug-in for WordPress, supports API interface, and is suitable for access to various platforms.
• Mollom : Provides content analysis and behavior recognition, but is now closed.
• Cloudflare : Identify malicious requests through its firewall rules, suitable for sites with a certain amount of traffic.

Basically these commonly used methods. Not every website needs to be deployed all, and you can choose two or three combinations based on your own situation. The key is not to let spam comments enter the database, rather than clean it up afterwards.

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