When withdrawing on MtGox, you can check the option "Use green address" to cause your coins to be sent through the address 1LNWw6yCxkUmkhArb2Nf2MPw6vG7u5WG7q (or pass the option green=1 to the withdraw.php API).
https://bitcointalk.org/index.php?topic=48170.0&&That thread is from 2011.
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We are thinking of rotating the MtGox green address once in a while, with new green address announced ~1 month in advance.
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Where do they make the announcement? What use is a green address if they don't make it easy for everyone to know what the current green addresses are? Shouldn't the green address be publicly identified on their website somewhere? Are they still using the same green address from October 2011, or have they added additional green addresses since then?