I would apply section 230 on the basis of an entity’s principal commercial product. If an entity’s main product is platforming, i.e., its main paying customers are content providers, it’s a platform. But if the company sells content or eyeballs —if readers or advertisers are the company’s main revenue source — the company is a publisher. Platforms should be protected by section 230, publishers by NY Times v. Sullivan; (Here’s a longer, ad-focused version.)