"Facebook must answer these serious allegations and hold those responsible to account if there has been political bias in the dissemination of trending news," said Senate Commerce Committee Chairman John Thune (R-S.D.) in a statement. "Any attempt by a neutral and inclusive social media platform to censor or manipulate political discussion is an abuse of trust and inconsistent with the values of an open Internet."
Thune sent a letter to Zuckerberg after Gizmodo reported allegations that the human curators behind the company's "Trending" feature omitted topics popular with conservatives and didn't include stories from conservative news outlets.
Thune's letter to Zuckerberg asks a number of questions, including whether "Facebook news curators in fact manipulated the content of the Trending Topics section, either by targeting news stories related to conservative views for exclusion or by injecting non-trending content."
A Facebook executive said Tuesday that an initial review found "no evidence" to support the bias charges.
The South Dakota Republican also asked for more details on the guidelines Facebook has said stop the curators of the trending section from suppressing conservative news outlets.
"If Facebook presents its Trending Topics section as the result of a neutral, objective algorithm, but it is in fact subjective and filtered to support or suppress particular political viewpoints, Facebook?s assertion that it maintains a ?platform for people and perspectives from across the political spectrum "misleads the public," Thune wrote to Zuckerberg.
http://thehill.com/policy/technology/279361-top-republican-demands-answers-over-alleged-facebook-political-bias