Twitter’s head of brand safety and ad quality is leaving, the second departure of a top safety executive this week. A.J. Brown, who worked to assure advertisers that the microblogging site is a safe place for them to place ads, is exiting, according to a Wall Street Journal report, citing people close to the situation. On Thursday, Ella Irwin, Twitter’s head of trust and safety charged with handling content-moderation decisions, reportedly quit, according to another Journal report.

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