What was Slack's key conceptual innovation (not features) over its competitors that enabled it to grow so rapidly?

I'd say more than just features, they were the ones who found a problem and solved it. There positioning was different than the other Instant messaging apps. They had positionining statement : "Where work happens"; hence, they are positioned as a work collaboration platform where as all the others like Flock came after them. They had the first mover advantage. Second thing is, they rolled it out for free initially. So people who were using Hangouts or other chat messengers in their offices started giving it a try. Hence, according to me, it was not the features that mattered but the gap they filled in the market with a great product. It was the word of mouth marketing that worked extremely well for them.They sponsored podcasts with big and loyal listeners, and tried to build brand awareness using them. They did subtle marketing with these podcasts and made the people aware of the name "Slack", until they started their own podcats which gained viral popularity. This virality was aided by a well worsed social media startegy from facebook and youtube, which would just make the people come to listen to their podcasts once, and once it was done, there was no looking back.

Arnav Mahajan has added some good points.Will probably need a more detailed research to answer this well, but off the top of my head, these were some reasons:1. 10x better solution: Before Slack, teams were using email and were hating it. Slack offered a more organized, personal and real time alternative to email.2. Early adoption by influencers + Networking effect3. 3rd party integrations = free marketing: This gotta be their smartest idea. By letting other companies add unique features on top of Slack, they not only got free marketing but also left the competition behind.

Slack's growth is insane ! - Vishal Sanap

Vaibhav askedon {{::getFormatedLocalTime("2017-12-09T12:23:11.670Z", {without_time: true})}}

Is it better to deploy app in multiple phases or should we deploy all features at once? While releasing app for the first time

Hello everyone,I am creating an android application and most of the features of the application has been completed. But when i completed one feature i got some others functionalities in my mind which i can deliver. So my question is what should be the best way while launching your app for the first time. Should i deliver all the functionalities at once or should i keep some functuionalities for the next release. I am also aware with the fact that giving more functionalities also increases the development time (when you are working alone).