When publicly-traded corporations reach record valuations, articles in the media often compare such valuations to the GDPs of countries throughout the world, typically in the form "Company X's valuation of Y is now larger than the GDP of all but Z of the world's countries..."
For example, a Fortune article from Nov. 2014 states:
At this point, Apple’s market cap is higher than the gross domestic product of all but 19 of the world’s countries, coming just behind Saudi Arabia (GDP of \$745 billion) and ahead of Switzerland (\$650 billion), according to data compiled by the World Bank.
This doesn't seem like a meaningful comparison to make, given that GDP and market cap are very different metrics.
Similarly, a Business Insider article compares corporate revenue to countries' GDPs. This is intuitively a better comparison than market cap to GDP, but wouldn't comparing profits to GDP be a more accurate measure?
In summary, what are the best metrics for comparing the performance of companies to the performance of national economies?