From
https://www.mybitcoin.com/contact-us.php :
MyBitcoin LLC
Main Street, Box 556
Charlestown
Nevis, West Indies
So good luck with suing them! You will need it.
There is probably a potential lawsuit against mybitcoin.com for negligence.
Numerous users have complained about the theft of bitcoins from mybitcoin.com
http://forum.bitcoin.org/index.php?topic=20427.0If they were aware of the potential security breach and did not take adequate measure to protect their members they could be liable
So let me get this straight:
1) There were no security problems at mybitcoin.com
2) mtgox was cracked
3) Some users were so f***ing stupid to use the same username and password on both sites
And you claim 3) is the fault of mybitcoin.com? I don't see any reason why they should reset any passwords due to the Mt. Gox issue. To be honest, as a user of Mt. Gox I was really annoyed that I had to reset my password at some other sites, just because some users were too stupid to take minimal security precautions.
Being just stupid is one thing, suing others for your own stupidness is another thing - and not acceptable to me.