how can you tell which wallets are cryptocurrency exchange wallets?

[pufuletz]

Every once in a while, I read something about an exchange wallet (like Poloniex's, Bittrex's, others) --- typically when they get hacked.

How do peolple know which wallets are exchange wallets anyway? How does http://coinmarketcap.com know?

Do the exchanges disclose this? Even if they do, how would people be able to confirm independently / empirically which blockchain wallets are exchange wallets?

[spatula]

Exchange wallet just means the wallet that the exchange owns. Like when you send (deposit) coins to your exchange account, the exchange technically has control of your coins. If you are holding said coins, keep them in your personal wallets.

[poblico]

When exchanging coins you HAVE to put all your coins in a pool with other people and get "credit" of amount, this is so you can transfer ownership of the coins in exchange for ownership of other coins. (It's also the reason when an exchange gets hacked every body are screwed)

So all exchanges must have a wallet with all funds in one shared pool right? (shapeshift connects to existing exchanges)

Apart for the typical client wallet where you own your keys there are also hybrid wallets where the user controls the keys like coinomi or coinvault.io (for alt coins) the wallet service will normally advertise that.