Farmville was a blatant ripoff of Happy Farm - it just happened to be the first clone to hit the U.S. market from China and be successful.
What disappoints me about the current social gaming genre is how many games what would have otherwise been decent tycoons are ruined with slot machine mechanics.
You're the first person I've "met" who got SimIsle. Maybe I need to give it another try...
Happy Farm was legitimately a social game - even further than Farmville ended up being. In fact, almost two thirds of the Chinese population that played admitted they did so only so they could steal crops from their friends.
It's almost a case study into the Chinese culture unto itself.