Bytedance, the creator of the news aggregator Jinri Toutiao, the video-sharing service Tik Tok and a fleet of other entertainment apps, is in discussions to raise new funding that would value the business at $75 billion. A $75 billion valuation would make Bytedance one of the world’s most valuable private tech companies. Last year, it bought Musical.ly, a video-based social network popular with teenagers in the United States and Europe, and folded it into Tik Tok. Musical.ly had been notable for being one of the rare Chinese social media companies to have attracted a significant following outside of China. Zhang Yiming, Bytedance’s founder and chief executive, offered a display of contrition after a joke app, Neihan Duanzi, was shuttered. He apologized for the company’s failure to respect “core socialist values,” and thanked China’s government for enabling tech start-ups’ rapid development.