As of April 23, 2012, there are new features in Google+:
1) Users can share YouTube videos and inline images in Gmail messages with one click.
2) Users can add Google+ users to Circles directly from Gmail messages
3) There is a new People Widget in the upper, right hand corner which shows the last three images a contact has sent. If you click on the image, it takes you directly to the email message the image was sent from.