The Slack Platform Roadmap
medium.com
medium.com
Just about every messaging system has support for this: ICQ, MSN Messenger, Jabber, Yahoo Messenger, Google Talk and now Google Hangouts, HipChat, etc. Even with IRC there are cheap ways to simulate it. It's really hard to get used to not having it after making good use of it for almost 2 decades.
I never used any of those much, but starting using Slack when I joined a company where it was ubiquitous. I never saw anybody care about declaring an away message. People at any point could be busy and might not answer, but they were rarely "away". The culture was just to assume that people were available, and if not that they'd reply when they could.
I work for a slack competitor that has away messages, and I'm jealous of Slack's willingness to ignore the old interface patterns and implement the simplest solution possible that makes the most sense for larger group users, new users, ignoring the expectations of the smaller group of users, old-time users.
Question is, why the anonymity?
IRC has it built-in: the AWAY message.
To set:
AWAY :I've gone to the dentist
To clear: AWAYI actually prefer Slack's Calls than any other group calling services out there now.
In the framework of this presentation, slack is currently in the 'Engage' phase of the platform. They're all about openness and building something great.
But code is law, and eventually their APIs will be used for something they dislike. Building on a platform is always going to be like snatching pennies from in front of a steamroller.
1 - Give devs the option to extend the UI via fly-in panels (like rocket.chat does)
2 - Update API to support comms with 1