According to the Journal of Medical Internet Research, "Chatbots are [...] increasingly used in particular for mental health applications, prevention and behavior change applications (such as smoking cessation or physical activity interventions).". They have been shown to serve as a cost-effective and accessible therapeutic agents for indications such as depression and anxiety. A conversational agent called Woebot has been shown to significantly reduce depression in young adults.
Interestingly, the as-yet unnamed conversational agent is currently an open-source project, meaning that anyone can contribute to the development of the bot’s codebase. The project is still in its earlier stages, but has great potential to help scientists, researchers, and care teams better understand how Alzheimer’s disease affects the brain. A Russian version of the bot is already available, and an English version is expected at some point this year.
Since 2016 when Facebook allows businesses to deliver automated customer support, e-commerce guidance, content and interactive experiences through chatbots, a large variety of chatbots for Facebook Messenger platform were developed. In 2016, Russia-based Tochka Bank launched the world's first Facebook bot for a range of financial services, in particularly including a possibility of making payments.  In July 2016, Barclays Africa also launched a Facebook chatbot, making it the first bank to do so in Africa. 
A malicious use of bots is the coordination and operation of an automated attack on networked computers, such as a denial-of-service attack by a botnet. Internet bots can also be used to commit click fraud and more recently have seen usage around MMORPG games as computer game bots. A spambot is an internet bot that attempts to spam large amounts of content on the Internet, usually adding advertising links. More than 94.2% of websites have experienced a bot attack.
The first formal instantiation of a Turing Test for machine intelligence is a Loebner Prize and has been organized since 1991. In a typical setup, there are three areas: the computer area with typically 3-5 computers, each running a stand-alone version (i.e. not connected with the internet) of the participating chatbot, an area for the human judges, typically four persons, and another area for the ‘confederates’, typically 3-5 voluntary humans, dependent on the number of chatbot participants. The human judges, working on their own terminal separated from one another, engage in a conversation with a human or a computer through the terminal, not knowing whether they are connected to a computer or a human. Then, they simply start to interact. The organizing committee requires that conversations are restricted to a single topic. The task for the human judges is to recognize chatbot responses and distinguish them from conversations with humans. If the judges cannot reliably distinguish the chatbot from the human, the chatbot is said to have passed the test.
Despite all efforts during almost half a century, most chatbots are still easily uncovered, but over the next decades they will definitely get smarter and finally we will distinguish human beings by them giving us silly answers as opposed to the much smarter chatbots. All of this will really start accelerating as soon as one single chatbot is smarter than one single human being. They will then be able to learn from each other, instead of learning from human beings, their knowledge will explode and they will be able to design even better learning mechanisms. In the long run, we will learn language from chatbots instead of the other way around.
2a : a computer program that performs automatic repetitive tasks : agent sense 5 Several shopping "bots" will track down prices for on-line merchandise from a variety of vendors.— Sam Vincent Meddis especially : one designed to perform a malicious action These bot programs churn away all day and night, prodding at millions of random IP addresses looking for holes to crawl through. — Jennifer Tanaka
Since the steep rise of available hardware and software platforms lately, nowadays chatbots are available everywhere. Originally, they were very tight to computers, then exchangeable through tapes, discs and floppy discs, but since the Internet era they have been widespread. For example ancient chatbot Eliza is now also available on iPhone, while famous chatbot A.L.I.C.E. is available on Facebook.
Enter Roof Ai, a chatbot that helps real-estate marketers to automate interacting with potential leads and lead assignment via social media. The bot identifies potential leads via Facebook, then responds almost instantaneously in a friendly, helpful, and conversational tone that closely resembles that of a real person. Based on user input, Roof Ai prompts potential leads to provide a little more information, before automatically assigning the lead to a sales agent.
Tay, an AI chatbot that learns from previous interaction, caused major controversy due to it being targeted by internet trolls on Twitter. The bot was exploited, and after 16 hours began to send extremely offensive Tweets to users. This suggests that although the bot learnt effectively from experience, adequate protection was not put in place to prevent misuse.
The evolution of artificial intelligence is now in full swing and chatbots are only a faint splash on a huge wave of progress. Today the number of users of messaging apps like WhatsApp, Slack, Skype and their analogs is skyrocketing, Facebook Messenger alone has more than 1.2 billion monthly users. With the spread of messengers, virtual chatterbots that imitate human conversations for solving various tasks are becoming increasingly in demand. Chinese WeChat bots can already set medical appointments, call a taxi, send money to friends, check in for a flight and many many other.
“We believe that you don’t need to know how to program to build a bot, that’s what inspired us at Chatfuel a year ago when we started bot builder. We noticed bots becoming hyper-local, i.e. a bot for a soccer team to keep in touch with fans or a small art community bot. Bots are efficient and when you let anyone create them easily magic happens.” — Dmitrii Dumik, Founder of Chatfuel