Ask PG & HN: Subscription or Data Licensing, as business model?

I am not sure if PG answers these kind of questions but it's worth asking.

I am working on a simple service to sort reading material. Something, say, like Read it Later or Instapaper which does some sorting based on some social media things. (Of course this is not full idea but that hardly matters).

Now there are two ways I can go:

Subscription based Service There will be a free account but for better experience and features. You pay, say, $5-$15 a month. That's simple charge user for what they use.

But then is asking user to pay for what otherwise is free, is that cool? And not even sure if "technically" selling sorted links is cool with Publishers.

Free Service, Sell Data: Somewhat what Crowdbooster is doing? Service is free but data of, say, reading habits can be useful for advertisers or publishers. That can be licensed.

What are your thoughts on both business models (if I can call them that).