The stuff that could have been invented 5-10 years ago but was not interesting enough to warrant the effort
I suppose I wouldn't mind having a fridge which knew what was in it, so I could check what I needed to pick up on my way home before I left the office. But I doubt the system could be made smart enough that it actually saved me more mental effort than it consumed. The low-tech version is to simply put cameras in your fridge so that you can check its contents remotely... but even if I had this set up I doubt I'd use it all that often.
Maybe I'm being overly harsh on the smart-fridge idea. But I think it's representative of a huge class of dumb ideas: let's use fancy technology to save some minor effort for the consumer, at the cost of the consumer now having to go to the effort of acquiring, learning and maintaining yet another fancy piece of new technology. Screw it, I want my microwave with dials back.
Consider this essay:
http://www.taquitos.net/chipworld/articles/snaxpo-learned.sh...
> Convenience in foods will continue. Anything that takes the steps out of a process will become successful. Witness the "chip/dip" combo packs that Frito Lay is now selling. Open the package, you have chips and dip right there. No need to go to the fridge! At the testing area, Jays demonstrated a combo pack that had mini pretzels and honey mustard that was extremely tasty. Other examples included a pre-cooked baked potato that includes the sour cream, butter and salt and pepper inside the package. All you have to do is nuke the potato for a few minutes and you've got instant lunch.
To solve this, you'd need human interaction etc. etc. and you soon arrive at a point where you just stock the frigging thing yourself anyhow. For a one-household effort, this really doesn't warrant the effort.
A different story could be approaching it as some sort of communal effort, say the combined amount of fridges in one multi-story house or student dorm. If you could plan your meals /assisted/ by your fridge and it could tell you that the guy next door has eggs that are free, you wouldn't need to buy a whole carton just because you want to bake a cake, thus possibly reducing waste.
In the end, this puts us back to the old privacy implications versus efficiency problem that remains largely unsolved.
Oh, and they should start putting windows in the doors so that people don't stand there with the door open, thinking about what to eat.
I'm pretty sure all of that is trivial for a good engineer to wire up these days. Though if we ever had a 'smart' enough fridge, I could also see people integrating things with the various social dieting apps or whatever.