I can't speak as a big Zynga user (indeed, I don't play their games at all) but my wife is a total addict. Zynga's games, as far as I can tell, and certainly th

I can't speak as a big Zynga user (indeed, I don't play their games at all) but my wife is a total addict. Zynga's games, as far as I can tell, and certainly the older games, don't make much use of capabilities that Flash offers over plain old HTML4 + JavaScript. So, in essence they picked Flash because it _might_ have let them make interesting games with what was at the time a ubiquitous engine, but in fact they made rather uninteresting games that could have been done without it, and this has cost them dearly.