the concept of giving ANYONE my bank account number absolsutly terrifies me.
I trust paypal with the info.
Dwolla I gave a throwaway account that I keep less then $100 at a time.
giving an individual my account number for a member to member transfer, I dont think so.
If you give them enough info to complete the transfer they also have enhough info
to create ACH transactions and empty your account in seconds.
In the case of withdrawals, yes, you would. There are protections from the bank often times that prevent fraud if you detect it. You run the same risks with VISA cards.
In the case of funding a trade account, all the trader sees is the last 4 digits of the account number usually.
This all hinges on the reputation of the exchange. I am assuming the exchange is reputable in this poll.
EDIT: PayPal has too many charge-backs and is known to cancel accounts outright. This is not an option for an exchange on a large scale. Even credit cards through merchants are scary because of charge-backs.