If I may, linkedin does allow users to correspond with each other using both mail clients or directly through their platforms. The part that I am not too sure about is how does Hum solve user problems that whatsapp/wechat can't. The gap I find as a user is that unless there are ways for Hum to integrate with the fragmented contact databases we have across the various social networks (i.e. my gmail, 1k+ linkedin contacts, facebook friends, twitter correspondence etc) and make my life easier, I may not venture and try yet another chat platform.