The Freenode IRC network has a channel called #whatwg where some of the more active WHATWG community members hang out. Feel free to join us!
Note that if you go to IRC to ask a question, it might take a while to get a reply. It can pay off to stick around for a couple of hours or more.
If you want to run a bot, let us know. If they are useful, e.g. providing logging facilities, then they are more than welcome.
Logs for the #whatwg channel can be found here:
To leave a message to someone who is offline you can do:
Source/docs for botie is at https://github.com/w3c/infobot
The simplest way to get started with IRC, if you are not familiar, is by signing up for a free IRCCloud account. Once you've done that, you should be logged in to the Freenode server by default. All you'll have to do is join the #whatwg channel. If you tell your browser to use IRCCloud for irc:// links, then just clicking this link should also take you there.