Google groups are the best solution if you want to have a working mailing list without having to deal with setting up and maintaining a mail list server yourself (which is a non-trivial task and a serious responsibility). E-mail still stands unconquered as a practical tool for people who want to get things done with minimum bullshit. What else would you propose they use instead?
Github how? I've yet to see Github being used well for any kind of discussion other than issues.
Three major drawbacks compared to mailing lists: it's on-line, it's proprietary, it sucks for searching and filtering (seriously, the few tools it gives you are a fraction of what you get in any e-mail client).
You have good points; I was commenting on the use as issue tracker which projects seem to do and the use of the actual Google Groups interface. If you use it with an email client that's quite different and yes, you are right there although I don't find it optimal the non proprietary and online nature annoy me too. Maybe I shouldn't use the client and just sign up for the list and respond via email.
