Falling interest rates should lead to a more active housing market.The news this week from the Federal Reserve has sent Zillow (Z -1.68%) (ZG -1.41%) shares sharply higher. According to data provided by S&P Global Market Intelligence, the real estate tech company's shares jumped by as much as 14.8% this week and were up by 12.7% for the week as of 10:30 a.m. ET Friday.Interest rates and the housing marketThe Fed cut the federal funds rate -- its benchmark short-term interest rate -- by 50 basis points (0.5 ...