"exponential growth is going to come to an end"

We're literally just hitting the part of economic development where the highest impacts to output are not resource intensive but rather intellectual property intensive, and also difficult to measure by a traditional measure like GDP. How do you measure the economic impact of say, wikipedia, in terms of GDP? Its free, it raises funds only through donations, and it has immense value. We're just getting started with exponential growth, and we're just getting started because we're finally decoupling growth from physical resources