Like I said, possible violations. It could be that internet banner ads are new enough that the FEC is still getting their arms around such. But IMO the same rules regarding access that apply to TV and radio should apply to Google, Twitter and other sites that generate banner advertising.
General Michael Flynn said that individuals on Twitter were a huge influence in favor of Trump. So Trump save several million dollars and Twitter is now labeled as dirty. FEC has never censured any Democrat. Dirtier than dirt.