Troy Hunt has been blogging about this for a while. Troy is a good guy who blogs extensively on security matters. I don't see any risk in putting your details in here.
His recent posts on pwning peoples phones and tablets while they were at his conference talk are pretty amusing. Shows just how insecure things really are.
http://www.troyhunt.com/ http://www.intodns.com/haveibeenpwned.com (forwarded from haveibeenpwned.azurewebsites.net) http://www.whois.com/whois/haveibeenpwned.com
Seems legit.