The US Senate Commerce Committee — which has jurisdiction over media issues, consumer protection issues and internet communication — has sent a letter to Mark Zuckerberg requesting answers to questions it has on its trending topics section. The letter comes after Gizmodo reported yesterday on allegations by one former news curator, who worked for Facebook as a contractor, that the curation team routinely suppressed or blacklisted topics of interest to conservatives. That report also included allegations from several former curators that they used a "injection tool" to add or bump stories onto the trending module.