I want to know the answer to the following question:
What key feature is not supported by the free version of Live?
All the background I'm provided with is that "A Live Free account does not generally support multiplayer gaming; however, some games that have rather limited online functions already, (such as Viva Piñata) or games that feature their own subscription service (e.g. EA Sports games) can be played with a Free account.". Is that enough to answer the question?
Answer: yes