Bot refers to software or a computer program that runs automatically it can include the automated software or may also refer to the crawlers which capture the web content for search engines. For instance the chat BOT which is generally seen in online chat rooms have an automated system according they greet people when they enter the room. Similarly they also execute other actions as per the command given to them. In case of web searching the BOT helps the search engine by searching for the relevant information. It crawls over the different web pages, captures the information given on those pages and shows the relevant in the search results. Thus they are responsible for browsing the different documents stored on the internet and coming with the required information.
The BOT is considered to be very useful to the search engines and is used by them. Apart from the web searching bots and the Chat bot other kinds of Bot are also there. The main thing is that they work like a Robot wherein they take in a command and execute action as per the command. They help search engines to retrieve millions of documents and record the content of those documents. The BOT then creates special catalogs for the sites that have been crawled and these are shown in the result shown by the search engine.