Don't hold me on this but I believe it's a DarkWallet address.

http://bitcoin.stackexchange.com/questions/20701/what-is-a-stealth-address

Most of your answer will be on the first and second answer.

Maybe, it just an address that use for protecting the main address.

Maybe we should ask Gavin or Theymos 

Four different explanations for what happened 
And chances are that maybe non of them is correct 

It doesn't have anything to do with stealth addresses. The output uses OP_RETURN, which is an instruction designed to store data in the block chain. I don't know why they label it "Stealth Address Data". It is not an address.

A way for an advertiser to create an incentive for greedy people to fill the forum with thousands of posts of completely useless nonsense.  The advertiser offers a small payment in exchange for the user to add the advertiser's ad to the user's signature space.  The user is required to create a particular number of posts on the forum so that the advertiser feels that the ad will get noticed.  Since the average greedy unknowledgeable user doesn't have enough useful and well thought out things to say to meet the advertiser's quota, they end up just spamming threads all over the forum with useless drivel.  Several of the regular forum users have taken to blocking (using the "ignore" link) all users with a signature ad campaign in their signature.  Therefore, by participating in such a campaign, you significantly increase the likelihood that helpful and knowledgeable users will never see anything that you post here.