We all have done it — received an email, hit reply all and continued a conversation oblivious that we are essentially are creating a kind of spam in everyone's inbox, reducing people's productivity and abusing their attention. Problem gets infinitely worse when folks put 50+ people on "CC." It is 2014, and by now we should know better. Like someone said, Reply All is Evil.
Why can't email clients — Apple Mail, Mailbox, Outlook, AirMail and Gmail — have a built in feature where when sending an email to more than a preset number of people (set by sender) those being copied are defaulted to "BCC" unless specified. It is a good way to reducing the mass-mail-reply-all clutter. Of course, someone can build a Chrome extension to add this functionality to Gmail. Together with Mute-button, it would go a long way towards a sane inbox.
PS: I tweeted about this yesterday and here are some good responses #1 #2 #3 #4 #5