So buying Instagram certainly looks like a good trade - it would be worth a lot more if it was selling today. But as a strategic move, it's looking increasingly irrelevant. Is FB going to buy Whatsapp, Snapchat, Line, Kakao and the next ten that emerge as well? Sure, some of those will disappear, but it doesn't look like FB will crush the competitors the way it did on the desktop. On mobile, FB will be just one of many.
Just maybe, Facebook might have been better off rethinking the core product instead of buying what turned out to be just one of a swarm of alternative services.
This, of course, prompts comparison with another (in)famous acquisition - Flickr's purchase by Yahoo. There was a period when AOL and Yahoo went around buying up lots of cool new web services as their portal model came under threat. They then generally mismanaged them, but that wasn't really the point. No matter how well they ran these acquisitions, they couldn't buy every great website that there was. Neither can Facebook.Benedict Evans
Apparently that hasn’t stopped them from trying: Snapchat rejects $3bn Facebook buyout!