SEO Glossary > Bot (robot, spider, crawler)

Bot (robot, spider, crawler)

A bot is a software application or script which is programmed to carry out a series of tasks automatically over the internet. The most common example are bots created by search engines that crawl websites on the world wide web, fetching and indexing the content on web pages. Another type of bot is a chatbot that is employed by companies to answer customer service questions. There are also bots that are created for malicious purposes like carrying out DDOS attacks which bombard web servers with communication with the aim of preventing them from handling legitimate web traffic.

Can bots get past CAPTCHA?


A CAPTCHA test is designed to see if a website visitor is human or a bot. The tests present a series of distorted numbers or letters. The reason these tests work is that bots are unable to read distorted letters. However, advanced bots are now able to use machine learning to identify these distorted letters. To deal with this, Google now offers reCAPTCHA, a more sophisticated test that uses real-world images that machine learning can't decipher.

What are bots used for?


The vast majority of bots are used for web crawling. These bots are automated scripts designed to fetch and analyze information on web servers. Other bots, called chatbots, are designed to simulate human communication. These bots can do this either by using pre-determined scripts or by using advanced machine learning or natural language processing. Bots have many other functions such as posting to social media accounts, replacing words in headlines, or finding the best prices on products. 

Can hackers use bots?


Hackers can use bots to infect computers with malware. What makes this dangerous is the bots are able to collect data and passwords. This information is sent to the hacker's device. Hackers try to infect a large number of computers and network them together. This is called a botnet. Botnets can be used to commit financial fraud, identity theft, malicious software distribution, storing illegal content, the mass mailing of spam, and can collapse websites through massive attacks.