Some of Facebook's top executives will face questions from TDs and Senators today on the Cambridge Analytica scandal.
The Oireachtas Communications Committee is looking into the impact of social media on elections and referendums, like the upcoming abortion vote.
Appearing today are Vice President of Global Policy Joel Kaplan and the Head of Public Policy for Ireland, Niamh Sweeney.
The Data Protection Commissioner Helen Dixon will also give evidence about her role in protecting citizens' personal information.
There'll also be scrutiny of the Online Advertising and Social Media (Transparency) Bill 2017.
Committee chair Deputy Hildegarde Naughton wants to hear whether the commissioner needs more powers.
"I really feel it's important that we have Helen Dixon come before the committee to outline areas where, if she feels that there are areas where she needs greater powers, we as an Oireachtas certainly need to step in to facilitate that".