Efforts by servers hosting websites to counteract bots vary. Servers may choose to outline rules on the behaviour of internet bots by implementing a robots.txt file: this file is simply text stating the rules governing a bot's behaviour on that server. Any bot that does not follow these rules when interacting with (or 'spidering') any server should, in theory, be denied access to, or removed from, the affected website. If the only rule implementation by a server is a posted text file with no associated program/software/app, then adhering to those rules is entirely voluntary – in reality there is no way to enforce those rules, or even to ensure that a bot's creator or implementer acknowledges, or even reads, the robots.txt file contents. Some bots are "good" – e.g. search engine spiders – while others can be used to launch malicious and harsh attacks, most notably, in political campaigns.[2]
This chatbot is one the best AI chatbots and it’s my favorite too. Evidently it is the current winner of Loebner Prize. The Loebner Prize is an annual competition in artificial intelligence that awards prizes to the chatterbot considered by the judges to be the most human-like. The format of the competition is that of a standard Turing test. You can talk with Mitsuku for hours without getting bored. It replies to your question in the most humane way and understands your mood with the language you’re using.

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Sometimes it is hard to discover if a conversational partner on the other end is a real person or a chatbot. In fact, it is getting harder as technology progresses. A well-known way to measure the chatbot intelligence in a more or less objective manner is the so-called Turing Test. This test determines how well a chatbot is capable of appearing like a real person by giving responses indistinguishable from a human’s response.
“It’s hard to balance that urge to just dogpile the latest thing when you’re feeling like there’s a land grab or gold rush about to happen all around you and that you might get left behind. But in the end quality wins out. Everyone will be better off if there’s laser focus on building great bot products that are meaningfully differentiated.” — Ryan Block, Cofounder of Begin.com