added link to IRC web chat, archive and mailing list

README.md

 
 ## Contact
 
-__IRC:__ #marlin-firmware @freenode
+__IRC:__ #marlin-firmware @freenode ([WebChat Client](https://webchat.freenode.net/?channels=marlin-firmware), [Archive](http://energymonitor-dk.dns4e.net/marlin-firmware-log/))
+
+__Mailing List:__ marlin@lists.0l.de ([Subscribe](http://lists.0l.de/mailman/listinfo/marlin), [Archive](http://lists.0l.de/pipermail/marlin/))
 
 ## Credits