Sign a message with an address that you've posted on the forum and reply here. You want to suspend any and all trading activity on the account by getting a DT member to tag it.
Then PM theymos or Cyrus to reclaim the account.
Just looked back through my posts on the forum
https://bitcointalk.org/index.php?topic=601965.msg6995462#msg6995462./boostcoind signmessage BKqAh5ojyS7bkjaDHJEWXxMwKNUvUsNZak "message to Theymos and Cyrus, i own this address"
IMuyTLkGle9qt4Xu32sjNTnez0ZZUgwcKnhIGwy+vatz6SPdtQgbkLHLPaD0f+yb4B21wXQ5P5ubGOR+P+XE2e0=