This approach seems to use privacy information to recommend to users an audience for each Facebook post. It’s claimed that it balances the benefits of posting against the risks of sharing. I haven’t read the paper yet but my guess is that the algorithm does things like examine the privacy settings of friends and might exclude them from sensitive posts if they’re not up to scratch. This is not quite the ‘breakthrough’ the headline declares it to be, but it’s the sort of thing I’d like to see social network providers adopting.
They probably won’t, though. Users are not the customers of social networks and unless we pressure their operators to care more about user privacy it’s not in their interests.