First Google linked to dictionary.com then answers.com and now they are using their own service. Google Dictionary is providing some new features, you can mark with stars and also switch to translator resource for other languages.
I've known about their dictionary for quite some time. You don't have to access the dictionary directly to get definitions. To get definitions, put this into the search bar - " define: wordofchoicehere " Yugo,
I have seen it before but the opinion of others matters more, As dp members are always ready to help you.
I haven't seen or used it before. And google always brings something new and this is a great stuff from google.