Isn't this confusing the point a little. There have been lots of talent acquisitions, but I'm not sure how you'd classify Instagram as one.

For example it's been 7 months since Facebook took over and its still going, also they seem committed to keeping it going. Instagram was the most likely of Facebook's 1000s of competitors to actually grow big and disrupt the market. If they hadn't bought it Google would have bought them - since they desperately want a social network that has product/market fit.