Many Wikipedians have chatting open in one window and hop back and forth between it and other windows in which they are working on Wikipedia.
An IRC bot is a set of scripts or an independent program that connects to Internet Relay Chat as a client, and so appears to other IRC users as another user.
Note that IRC needs more care to maintain anonymity than Wikipedia editing does.
There's a couple ways you can connect, as seen at the top of the page, but everyone will be able to from here.
Often, an IRC bot is deployed as a detached program running from a stable host.
It sits on an IRC channel to keep it open and prevents malicious users from taking over the channel.