Lenders at Zopa do not (yet) select an individual borrower but rather select a market and a rate at which they want to lend their money. This is matched to borrower demand and if a match is found, money is lend out.

There is a 3rd party site tracking the development of the Zopa demand volume and charting it (daily, weekly, monthly, yearly). Recently the amount requested has gone down in most markets.

(Source)