
Limiting registration for services-services can use CAPTCHAs to prevent bots from spamming registration systems to create fake accounts.

Although this does not limit the overall number of votes that can be made, it makes the time required for each vote longer, discouraging multiple votes.

For example, identifying stretched letters or numbers, or clicking in a specific area. CAPTCHAs provide challenges that are difficult for computers to perform but relatively easy for humans.

CAPTCHAs are tools you can use to differentiate between real users and automated users, such as bots. CAPTCHA stands for the Completely Automated Public Turing test to tell Computers and Humans Apart.
