If I vet Al Qaida members on my platform, provide them services, continue to do it after several bombings, and keep their unencrypted mails and host their websites, I'm quite sure that I can be considered as an accomplice.
When are the executives of Twitter, Facebook, Google, being charged with these crimes? Any minute now?
Facebook was funded by Thiel, launched the day after DARPA shut down digital LifeLog and has long standing connections to intelligence agencies. Twitter is owned by the world's largest defense contractor.
These are government agencies acting as private entities.