Today!! This social media network set the stage for Jan. 6, then was taken offline.

Parler, the “censorship-free” social media platform extremists used to hype the Jan. 6 insurrection, is back after an almost one-year hiatus. Meanwhile, online trolls are targeting a video game company and calling themselves “Gamergate 2.0.” And lawsuits stemming from a 2022 extremist mass shooting could change the way...