Google requires the full content it indexes to be available to people following links from Google as well, so publishers make an exception to the paywall so they still get listed on Google.
Ok, so in the future should we post the Google link instead? If you found the article through Google, then I think this is fair. However, I don't know how long a Google link remains valid.
Nope - post the real link, and then there's the "Web" link under the title which will take you to Google, and can be clicked onto from there.
Unfortunately even that, with no prior visit to the site, did not work on FF for Android (maybe due to the age of the article?).