If you want to take backup of any of the google products - You need to open Google TakeOut App where you can archive all the data and you can download the same.
It will give in .zip format and you can archive multiple products at a time - but download depends on the data it has in each app.
By the Way - Orkut is shutting down from Sept 30th 2014 - So back up your Orkut data if you want.!
PLEASE SHARE - BECAUSE IN KNOWLEDGE
SHARING IS GAINING