Over the next couple of weeks Google will be rolling out a new ‘People Widget’ for Gmail which has been designed to help organise the content you share with your contacts. Once rolled out to your account it will appear on the right-hand side of your Gmail page and display messages, phone calls, and chats you have had with your contacts.
The new widget doesn’t require you to install a new plugin or do anything, it will just start appearing for Gmail users over the next couple of weeks.
Once the ‘People Widget’ has made it to your account, next to every email message, contextual information will appear about the contacts in each conversation including recent emails you received from them, relevant Buzz posts, shared documents and calendar events.
Facebook, Twitter and other social networking sites are not available within the widget at launch but maybe added as updates to the new ‘People Widget’ in the future.
Source : Gmail