In this location context how are に, で and にて different?

Question

I still have trouble with how に and で differ when dealing with locations, and I just stumbled across にて. Are these all interchangeable? How are they different?

• オンラインマーケットにて販売開始しました。
• オンラインマーケットに販売開始しました。
• オンラインマーケットで販売開始しました。

Answer 1

• "で" indicates the place of an action, or means by which it is performed
• "に" indicates the target of the action

In your example, "market" could mean a few things:

1. physical place
2. virtual place (for all intents and purposes just another place)
3. concept of a market (ie. the "thing" we think of when we imagine all those buyers and sellers in the economy)

So the meanings of your examples can be:

1. "で" Selling something at (ie. location) or through (ie. as a tool) the market.
2. "に" Selling something to the market (ie. the notional market, made up buyers and sellers, is the target of the action)

A better example to remember the differnces might be as follows:

[You're on a bus, pointing to an empty seat.]

ここに座ってもいいですか？
'Can I sit (in that empty seat)?'

but

ここで座ってもいいですか？
'Can I sit (here, where I'm standing whilst asking this question)?'

The first indicates with "に" the target of your desired action.

Whereas the other will make them wonder if you're completely sane, and if not, why you're even bothering to ask for permission to sit on the floor of the bus!!?

Answer 2

My understanding is:

マーケットにて販売開始しました。 ["にて" is just the formal version of "で".]
マーケットに販売開始しました。　　[Here, the action is taking place at the market.]
マーケットで販売開始しました。 [Here, the action is taking place in the market.]

Your example is a little difficult because one could be referring to a market you have to physically be in　（で）, and the other being like an online marketplace ("に"）. But in general, "に"　and "で"　are not interchangeable:

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