Edgeio provides some stats on its home page which indicate the number of listings it has gathered and the number of cities associated with those listings. These have both been increasing, and it is probably too early to use this data to judge the success of the system, but there is not yet any clear rapid growth. Here is the graph for listings.
And here the one for cities.
It is interesting to note firstly the large jump in both listings and cities - a sudden increase of data in the database, perhaps associated with a bug fix and recrawling or reparsing cached data. Secondly, there is a smaller increase in cities which has no associated jump in listings. Perhaps a problem with the location identification code which had no impact on the number of listings discovered.
The Alexa reach statistics show some growth, though very spikey:
The shape of this graph seems to be mirrored in the mentions of the URL as found in BlogPulse:
What we are looking for as a measure of success is non-linear growth in the number of listings (indicating that sellers are using the system and that the system is doing a good job of gathering the data) as well as similar growth on Alexa. One of the problems with the basic idea of Edgeio is that the passive manner in which you add listings provides no confirmation - sellers would have to go to Edgeio to discover if there stuff was picked up or not. Anywhere there is such a barrier, users will be dropped.