Take online videos. We spend billions of hours watching videos free of charge on YouTube. Some people — not the ones with cats — spend considerable time and money putting these together. But since they are available at no cost, this will not add to G.D.P. In that sense, what’s really being valued here is entertainment that’s protected by copyright, which in the era of viral videos is actually a declining share of what we watch.

Another arbitrary ring must be drawn around what is lasting in terms of added value and what is fleeting. Journalism is out, for example: barring the unlikely event that generations to come deem this essay an essential read, it will not be considered an investment in the G.D.P. accounts. Nor will blogs, despite the fact that since your time is worth something to you, they add value to those who take the time to read them.

But perhaps the most arbitrary part of this or any other G.D.P. revision is not the value of what’s put in, but the cost of what’s left out.

The failure to account for environmental degradation is a serious shortcoming of our measurement system. If we use hydraulic fracturing to reach deep pools of natural gas and in the process pollute groundwater, we will count only the value of the gas. There is no subtraction for the polluted groundwater or the greenhouse gas emitted when the gas is burned.

Finally, while this revision is a big deal for those of us in the field, does it matter to more normal people? For one, while it lifts the level of G.D.P. going back many years, it doesn’t have much impact on the growth rate. Over the past year, for example, the economy grew an anemic 1.4 percent, meaning we’re still in the same slog we were in before.

True, since the change raises the level of G.D.P. but doesn’t affect the debt, it will lower the debt-to-G.D.P. ratio, which in tandem with falling deficits should give policy makers the political oxygen to implement a jobs measure. But given the state of Washington these days, don’t hold your breath.

Too many Americans have felt disconnected from economic growth for a long time, something President Obama has stressed in recent speeches. Over this recovery, real G.D.P. is up 9 percent, while the typical household’s income is down 4 percent. So we’ll forgive you for not jumping for joy over the revisions.