NYT is trying to make a flexible paywall system which still allows limited linking to articles. It's a lot better than current systems like the Wall Street Journal Online. What do the users of the internet do? Try and abuse it to get stuff for free. What's going to happen is not that free speech on Twitter will be chilled. What will happen is that the NYT will go behind a tougher paywall, monetization be damned. Net users have to work with companies some, they can't pounce on every single attempt to make distribution cheaper and easier and try to make content free.