Yes android does keep contacts synced but the problem is that you still never know if you have the most up to the date and relevant information about your contacts. Only you know your contact and social information best. We let users create one profile with all of their contact and social information. So when you can add a contact on knok.me you're sending a request to their profile. The syncing solution is very complex. You're still creating duplicate copies of each contact. It is very unnecessary.