What do they do with them?
Like I remember how you could sell your old ipods and stuff and you'd get a price based on condition and useability.

Just wondering what they do with the phones.
Do they harvest personal information that can't be erased with a factory reset?

What are your thoughts with what they are used for?

In some phones there is (or was ) little bits made of gold. A local shop used to buy old phones, take out the gold bits then give the phones to Telstra for recycling.