Absolute Zero: The billion-dollar baby

So the entire Twitterverse / blogosphere was abuzz with Facebook buying out Instagram for a massive $1 billion dollars. Some felt this was a little too much for an app which, essentially, just adds filters to your photos - that too, camera photos.
Others feel that this is something that will go a long way given how closely entrenched photos are with FB. And after all, the iPhone is the most popular camera out there in terms of sheer number of uploads.
What do you guys think? Was it a useless buy? Was it a smart thing to do for FB? And of course, did Instagram 'sell out' by having a hugely valuated product and getting out without having the chance to develop something truly revolutionary themselves?
Speak away in the comments!