What Lives Where On The Web - Exim/exim GitHub Wiki
It might be a little daunting, first looking at Exim, to know what's where. This is largely because things are in flux.
Main Website
This is www.exim.org and contains online copies of the documentation and links to many more resources.
Wiki
In the past, this has been on wiki.exim.org as a Moin-Moin powered wiki. We lacked the human resources to adequately protect that from spammers and the install had fallen into a state of disrepair. We switched to Github for our wiki provisioning, which is presumably where you're reading this now.
Bug-tracking
This is hosted at bugs.exim.org.
Source Code
The master copy and developer public trees are available at git.exim.org.
We have set up GitHub alongside exim.org, so that in the event of failure of the master site, an existing site with established reputation as a “legitimate” copy of the Exim code will be available for people to trust.
Discussion
As Exim is a Mail Transfer Agent, it is perhaps unsurprising that most discussion takes place on Exim Mailing Lists.
Social Media
We are currently experimenting with the use of some social media outlets as a way of pushing out notifications which are more inclusive than our messages to the exim-announce mailing-list, but still generally of a broadcast approach.
Phil P has mentioned release candidates and releases on Twitter (which might yield no results if there have been no recent RCs or releases).
We had a Google Plus brand page but that service is shutting down.