As I posted on twitter[1], Slack is linkable. Not public, but if you can chat you see them. Gitter: public AND linkable. Async is a good argument; linkability is not. Slack's UI is good. Not perfect, but it's quite usable compared to all the alternatives[2]. People always underestimate the value of good UI. [1] https://twitter.com/zellyn/status/851818007248678912 [2] I've been on IRC on and off since 1993. It's much…
Have you never replied to an old forum post and been accused of 'necromancy'?
Have you never been late to reply to an email chain or a thread on a mailing list or forum?
There's no clear line dividing asynchronous versus synchronous communication. Even phone calls can be (partially) asynchronous – "hold on, let me check" let alone "let me call you back in ".
And similarly, if a group of people are responding to each other quick enough, even using an 'asynchronous' medium, then they're basically communicating 'synchronously'.