Just stumbled upon this site which offers cash back on purchases from multiple sources - both online and offline. They have a pretty large network of sites. Started by an Indian, first in the US, and recently started in India. Also has 2.5% cashback on flipkart.com book purchases
Site: pennyful DOT in
Link (referral link): <removed_temporarily>
Site: pennyful DOT in
Link (referral link): <removed_temporarily>