I am going to set up a Slack to communicate with my GSoC mentees. I know official policy is to communicate on this list, but especially with small setup questions the mentees might have, or gaps in their knowledge, that will create unnecessary spam for everyone. Larger-scale decisions will be posted here so they are on the record.
I didn't know what scope to make this Slack. So I called it apachecommonsnumbers.slack.com . If more people in commons are interested in this idea, I could change its name to apachecommons.slack.com, and we could all set up our own channels on it. It's free if that concerns anyone. Give me a +1 if you want to use it and I will invite you. Otherwise it will be lonely, just me and my mentees. :)