And you really think those 100'000 are actively clicking around all the time? There are no doubt spurts of activity where they do one, even two clicks per secon

And you really think those 100'000 are actively clicking around all the time? There are no doubt spurts of activity where they do one, even two clicks per second (most of which should not result in backend queries... surely Zynga has already implemented some kind of queuing mechanism to send those usage data in batches, rather than one by one). Most of the time, though, the users are most likely sitting there watching their crops grow - or even have another window open so they can pretend to work.