I got the same letter and like many things, I think there’s a lot of room for interpretation.
What I read into it is that subscribers (paid members) will get additional features, as well as additional content that’s not on the free side.
We don’t know what the paid features will be yet, but if they include making my profile page look like less of a train-wreck, I’m in.
Thing is — it’s all an experiment. In business you grow or you stagnate. So they try the subscriptions, and see whether people are reading the paywall content or just enjoying the additional features. And learn and tweak along the way.
The bottom line is that I don’t think we can reasonably expect anyone to run a business with no profit forever. How to make that profit, that’s the experiment on the table. I’m not sure ads would be a better route. That gets ugly fast.