Well, we're talking about copyright. And so long as you're not re-publishing anything, you're definitely fine.
Instapaper arguably is republishing, though the copies are private to each user. I suspect they could still be in trouble if sued, though.
Instapaper arguably is republishing, though the copies are private to each user. I suspect they could still be in trouble if sued, though.
Slightly off topic: I've been playing around with an idea for a service that would be able to share content this way - would make reading a lot more fun again.