Webirc
How webirc works:
- The user opens a mibbit client and requests a connect to, e.g., irc.blah.com
- The Mibbit backend checks irc.blah.com for matches in mibbit's webirc database
- If found the backend sends the user's IP along with a password (chosen by the server admin) to irc.blah.com
- The server checks all requests from 64.62.228.82 (webchat.mibbit.com) or 207.192.75.252 (widget.mibbit.com) for the correct password and then converts ident to "Mibbit" and @*.mibbit.com to the user's host name (most networks obfuscate the host for non ircops). The network now allows an (almost) unlimited number of users from mibbit's IP
see also: howto enable Mibbit on your IRC server