I've seen poor push notification quality increase uninstall and churn rates. I think the lesson is that many people are quickly annoyed with push notifications.
It is unethical, but the entire article is designed to convince people LinkedIn is outdated. It’s written on a blog that has 0 other submissions to hacker news. It was obviously a fluff piece written by someone trying to disrupt professional networks.
This really depends on what the company wants to adopt as “core”. They cannot be great at everything, so they must be careful in picking what topics to be experts in.
For example, maybe the Slack like app wants to be able to upload, distribute, and archive huge computer files. Everyone has tried to upload a file to an email, slack, or discord message and was told the file was too large. Our platform is going to be the platform for sharing 1TB sized files for collaboration purposes, with the goal of supporting 10TB in summer 2020 and 1PB before 2022.
The company should 100% make their own network protocol for transferring files.