One solution is analogous to the way, in many countries, you can’t drive a car until you’ve learnedhow to operate it under supervision and passed a driving exam. Similarly, new accounts should notget immediate access to all the features on an app. To unlock the features that are more abusable(to spam, harass, etc.), perhaps an account should need to pay some costs in time and effort.Maybe it just needs time to “ripen.” Maybe it needs to have enough goodwill accrued in somekarma system. Maybe it needs to do a few things that are hard to automate. Only once the accounthas qualified through this “driving exam” will it be trusted with access to the rest of the app.
I think this could be a really good direction, but it still seems unviable for implementing it in social media. Especially because it would drive user turnaround down, so many users would leave the site if they felt it was too much of a commitment to be able to use the full functionality of the site. I don't think any capitalistic social media site would realistically implement this unless they were forced to by the government or something. Maybe this idea should be iterated on a little bit, but it is a good start!