When Facebook launched the Portal TV video chat system in November, critics quickly shot down the idea of putting a Facebook camera and microphone in their homes. Reviewers, including me, worried that Facebook didn't take privacy very seriously.

But consumers have put those fears aside.

With people stuck indoors and seeking the best way to stay in touch with family and friends, the Portal TV is completely sold out on Facebook's website and from retailers such as Best Buy.

If you're unfamiliar, there are four Facebook Portal gadgets, including a big one that initially launched in 2018, two frame-sized devices and the $149 Portal TV, which uses your TV as a big video chat screen and provides really high-quality wide-angle lenses.

As I said when I reviewed it in November, Facebook Portal TV is my favorite model, since it lets you chat from a big-screen TV in your house, offering the most immersive experience. It's also dead-simple to use. That's the one that's sold out.

I've been using it more over the past several weeks to stay in touch with my brother, his wife and my niece in Santa Monica and my brother-in-law and sister in Seattle. This morning, I helped my mom and step-father set up their Facebook Portal TV, which my mom apparently bought just before they sold out.

"As people are taking measures to socially distance themselves and move to working from home, we're seeing increased interest in Portal, both in sales and usage," a Facebook spokesperson told CNBC. "We're pleased that we can help people connect with family, friends and colleagues during this time. And, like other companies, we're experiencing impact to our hardware production due to COVID-19. Some Portal models have been intermittently out of stock in select channels and regions. We are monitoring the situation closely and will continue to make products available as quickly as we can."