What is the difference between freemium and free?

Excuse me, could you clarify the distinction between the terms 'freemium' and 'free' in the context of digital products or services? I understand that 'free' implies no cost to the user, but how does 'freemium' differ, and what are the advantages or drawbacks of each model for businesses and consumers? Additionally, are there any examples of popular services or platforms that successfully employ a freemium strategy?