they're the middle man, they hold the amount, they release it to the seller based on whatever the condition of the sale may be.
Yeah, that's cool, but is the available total of my account include them, or are these taken off already, so for example when the Drop finishes, it won't take them off the available total?
This is unclear for me. For example - I had £300 on PP. Ordered stuff on Drop for £100. Activity list is showing £100 on hold - now, would the available amount on my PP account be £200 or £300?