As of July 2017, how big is the monero blockchain download and do you have to download the entire thing?
1 Answer
Blockchain size: Blockchain size on hard drive?
By default - yes. Although, you can use remote nodes to sync the wallet:
There's a way without having to download the blockchain but it comes with a trade-off: you need to give your viewkey to some service and then it does the scanning for you.
How does mymonero web wallet work?
Centralization of users around such services comes with some risk:
How can Monero defend against a "majority of view keys" attack?
That's why the plan is to bake-in the backend to the official release, and enable anyone to run his own back-end (like, you let your PC be synced, and hook your mobile to it).