They really only intrude into my life when a particularly overenthusiastic friend actually bothers to manually paste a link rather than hitting the share button
Distribution: No one actually visits our site to read it, we are reliant on third parties. At least 50% of our users come from Facebook, which helps mask if the other sources are even profitable by themselves.
Content: We publish content on other platforms which will slowly drain our visibility if they do too well.
Audience: We were in front of the curve and road it at its peak when Facebook opened up their newsfeed to content.
Technology: When one of our spam articles does really well with organic traffic, we spend a bunch of money to pay to promote it on the most visible channels.
As Facebook gave and took away Zynga's free traffic, so goes Buzzfeed's traffic.