The Profile Page of Salesforce Chatter can be customized to add additional TAB's. Here are the steps to do it. WEB TAB's and Visualforce TAB's can be added to the Profile page allowing to embed visualforce pages into the standard chatter profile page. Standard TAB's cannot be added.

STEP 1:

Navigate to Setup -> Create -> Apps


STEP 2:

Edit the 'Profile (Self)' and select the TAB's to add. In this case you can see that I have added the 'iSalesforce' TAB.

 

STEP 3:

This is the way it displays finally.