MekDC
My older experiment - client of DirectConnect network in PHP, JavaScript using Ajax. After some time I must admin that it's not very good, it's slow and buggy, graphically not the best so it's good mostly for study purposes. Exchanged data is stored in MySQL database where deadlocks occur 
but I didn't know that at the time of implementation...
Features:
- main and private chat on one hub
- user list (works OK only in small hubs)
- away mode with away message
- logon with registered nick which requires a password
- redirect support
