More complex measures would monitor producer/consumer activity and concentration by area – such as population, frequency, distribution and overlap of readers of newsgroups such as rec.pets.cats and rec.music.classical.
Equivalence measures, quantifying links between information exchanges and price-based markets outside, are possible but most likely fallacious. From "Cooking-pot markets" [3]:
For instance, calculating that since Linux users have, on average, much fancier hardware than Windows users and could therefore pay more for the software, the 6 million-odd estimated installed base of Linux is worth some $500 million in annual revenues. (This sort of valuation is faulty, as not everyone who uses free software would buy a full price version; however, the Business Software Alliance uses the same method to calculate losses through software piracy, where the same caveat applies.) The Apache Web server if paid for in cash ought to have revenues exceeding $500 million, given its commanding technical and market lead over regular commercial software.
More useful measures are possible. The health of an cooking-pot market economy can be measured through "macroeconomic" means. These could include: the lurker coefficient, indicating the concentration of active participants within a group and arrived at by calculating the ratios of contributions to contributors. A high lurker coefficient will typically reduce the motivation of the relatively small number of active participants to contribute free of charge and hence encourage barriers, analogous to the formation of guilds – or a shift to price-based model, as in the case of the Internet Movies Database, once all free, now advertising-based [7].
Easier measures could be possible with the widespread use of reputation networks; measures indicating the level of trust in the economy would indicate the economic activity, as it were. Measuring distribution or concentration of high reputations would indicate the level of wealth, analogous to the Gini coefficient.