That's the easy part. The hard part is scaling, marketing, and building a business/platform around the product so that you take it worldwide. Several people ha

That's the easy part. The hard part is scaling, marketing, and building a business/platform around the product so that you take it worldwide. Several people have built Slack clones and there's even multiple open source projects out there. Building a company and business at a scale like Slack is the incredibly difficult part and nobody has managed to replicate that.