News distribution: how has it changed?

In February 2016, BuzzFeed claimed that its comScore metric of about 80 million UVs represented less than one-fifth of its actual global reach. This illustrates a reality that many news organisations are struggling to come to terms with. Media outlets have the potential to reach a much wider audience by distributing their content on social platforms than they could hope to attract to their own properties. How should this inform editorial strategy, and what is the correct balance between pursuing a wider readership offsite, or catering to a loyal audience onsite? The distribution question isn't only one of platforms, but also one of devices. With a rapidly increasing proportion of publishers' traffic coming from mobile and tablet, how should news organisations adapt their output to address this shift in consumption?