What is a bot?

Bot is an automated program that performs a task more or less autonomously. Bots are software applications that run automated tasks over the Internet. Search engines use bots (robot, spider, crawler) to find and add web pages to their search indexes. Spammers often use bots to “scrape” content for the purpose of creating spam.

CAPTCHA is the most widely used anti-bot technique, which is used to distinguish between a human user and an automated bot by means of characters recognition task only humans can perform successfully. This test can stop bots from adding large amounts of spam to the internet.