Online grocery delivery is still only in limited, typically wealthy areas and is still more expensive. I think it also caters to people buying higher priced items such as more expensive meat or seafood, where the cost of delivering it is a small percentage of the value. Let's assume for a box filled with $5 and $10 items such as chicken, steak, coffee, etc that the delivery cost is $0.25 or $0.50 per item... that might not be a big deal for people here. But say you're buying boxes of $1.00 Rice in a box, or cans of beans and the cost of delivery makes a bigger difference in your cost per meal.

Items sold in online grocery services are also marked up higher than they are in stores, for example: "Celeste Frozen Pizza is 99-cents at ShopRite, $1.29 at Peapod and a whopping $2.69 at FreshDirect"(source: http://6abc.com/archive/8983520/)

It also assumes that people can be home for the delivery, neighborhoods like this might not be the type where you want $50 to $100 worth of groceries sitting outside your apartment building.

Making the actual payment is another thing to consider. Not everyone has credit or debit cards. It looks like online grocery sellers also can't legally accept EBT, Wic or other food programs for online grocery delivery: https://www.facebook.com/notes/peapod-delivers/why-we-dont-a...

Online groceries require planning, time, and at least for the foreseeable future will come at a premium cost. It's great for certain people but I hope it does not become the only option for groceries.