You may not have noticed it, but intel and counterintelligence agencies used Twitter heavily in the Obama era. Arguably, Obama's presidency was the one that put the nail in the coffin of trusting intelligence agency reports over twitter, but I think you could make a case it started with Reagan and cable news.

Basically, our elected representatives picked social media news sources as preferred trusted sources, and the groups interested in getting information and misinformation to them followed suit.