If your orkut account is hacked then only you are responsible for this , Orkut always recommend users to surf safe while accesing orkut but instead of this many users account is hacked .
Main reason for this is that users are spreading there account information , Orkut always says
- Never enter your Google Account login and password on sites other than orkut.com and other Google properties.
- Never check “remember me” when you’re on a shared computer.
- Never paste a URL or script into your browser while logged into orkut.com
Your orkut profile will be easily hacked by anyone if you unfollow any of above Points.