While I agree it would be a nice feature, it is a rather tall order and not likely something I will get to in the near future.

It would require some extra server component for a pop email account that receives the message to then be able to post programmatically into the forum. Doing this in a way that enforces the security of the forum and prevents spam would be a significant amount of work. And then even if implemented it would not be usable by most people in shared hosting because it would require a pop account that can execute custom code. The needed extra component could only be installed by those with full control of the server.

I'm pretty sure stackoverflow doesn't support any replies by email and that is the best forum I know of and the one I would like ours to emulate at some point.

So lots of work for a small improvement that wouldn't be useable by many people is not something I'm likely to work on soon, the cost/benefit ratio is too high.

Basecamp is a hosted service I believe, so they are able to do this since they can manage the pop email accounts and all other aspects of their servers. As far as I know Basecamp is not software that you can install on your own servers or in shared hosting. It would be much more challenging to provide software and support to enable others to do this than it would to implement it on your own servers.

Best,

Joe