Context : Essential to understand NetoCracy
Intro : http://www.orgnet.com/sna.html
Starts to get ethically icky when researchers actually make interventions into people's Facebook networks (with company approval) : http://www.zdnet.com/facebook-unethical-untrustworthy-and-now-downright-harmful-7000031106 (though I personally see how this happened and would probably have signed off on the ethics of something like this.) (See also CambridgeAnalytica scandals in the rise of FarRightPopulism
OTOH : I think what they found out knowledge worth having. But it's largely worth having in order to know the danger that corporations having this power present. You wouldn't want the academic study of this to be banned, and for the research to disappear into internal surreptitious tinkerings where no-one else ever sees the results except in private reports to the marketing department and advertisers.
TouchGraph Wiki analyzer : http://www.usemod.com/cgi-bin/mb.pl?TouchGraphWikiBrowser
Real example from industry : http://gates.comm.virginia.edu/rlc3w/sna.htm