Why does the Fed keep lowering rates?

We have seen the Fed cut interest rates to help stimulate
the economy. By lowering the cost of borrowing people will take on more debt
and increase their spending. However, the real winner may be businesses as
their cost of borrowing will go down and they can invest into new equipment or
expanding with much lower cost of managing their debt.

What could be the trouble with such low rates? Well if rate
stay low ...