We have been noticing some of these updates already and Google has now officially announced them.
Google Plus integration is coming to both Gmail and Google Contacts. Here are some of the features that would be arriving in the coming days:
You can see the latest posts on Google Plus from people who send you mails. You get the ability to add them to a circle of your choice from inside Gmail.
You can filter your mails based on different circles inside Gmail. This would allow you to go through emails in a more personalized fashion. Google Contacts also get integration with Circles for easy filtration and management.
The third feature is probably the coolest one. Google Contacts with matching Plus profiles would interconnect with each other. The benefit is that the contacts information would be updated as the other person updates his Google Plus profile. This means that you would always have up to date information about your friends and relatives.
Gmail would also allow you to share photos and videos from email messages. A new Share option would be available with attachments sent in emails.
Google Contacts also get a new updated permanent home at contacts.google.com.