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Apple might be working on a smart doorbell | TechCrunch
(techcrunch.com)
This is a most excellent place for technology news and articles.
Well no, it's not enormous, but Amazon is selling a couple million ring doorbells a year, and a couple million more of their cameras.
It's a sufficiently large market to hop into, especially if you can make a product that's easier to deal with from an ecosystem perspective than the incumbents, which isn't something I'd ever bet against Apple managing to pull off.