It [is] super valuable for a startup to get immedeate feedback. Especially valuable has been knowing - the first things the notice when they start using: where is sort? how do i add team members? do i have to prepay? - feature requests: it's painful to keep closing windows, need the ability to adjust windows, I also want to do this other thing you guys havent thought of. - Bugs: why am i seeing double messages.
In these words Arjun V. describes his experience from a startup of 8 people, with 100-200 customers. They create a WhatsApp group for a customer and stay with them right from onboarding onwards.
Source: Arjun V., Ask HN: How to effectively get feedback from users?