There has been much speculation about Zynga's numbers over the past few years. They gave out tantalizing tidbits but never enough to really know what they were making. As the acknowledged leaders of the F2P space, this is important information and, in the absence of real information, speculation ran wild.
However, in order to make a public offering, you have to "lift the skirts" as they say and so, buried deep in Zynga S1 filing with the SEC are these interesting tidbits:
This is a chart showing Zynga's gross income. The magic bar is the darker blue "revenue" bar as thats the actual money they took in.
This by itself is not much news, but when combined with this next chart, also in the document, it starts to paint a picture:
Looking at a total 2010 income of $698M and an average DAU of 217M, thats about $3.20 per active user account per year.
Honestly, thats better then I thought, though obviously a lot less then the $60 - $180 per account per year a subscription MMO returns.