I don't think Instagram set out to be acquired for $1B. That was just a pleasant after-effect. And here's pg's answer on what he would have done had he been pitched on Instagram:
"Instagram is the one we'd most likely have missed. It all depends when we'd talked to them. They were a kind of overnight success in traffic. If we'd talked to them even a day after they launched we would certainly have said yes. But before that it might have seemed too speculative."
When we invested in Instagram, it wasn’t actually Instagram. It was a company called Burbn, and the idea was roughly to build a mobile micro blogging service. Technologically, it was also different: an HTML 5 application rather than a native app...
Of course you never know what then happens. Instagram pivots to photos, and exits at ~$1B. But...
As Kevin iterated on Burbn, we made another investment in an excellent entrepreneur, Dalton Caldwell. Dalton’s company, Mixed Media Labs, initially built a product called PicPlz. PicPlz aime d to be a mobile photo sharing service...
Of course, now Dalton (as app.net) is doing what instagram (then as Burbn) set out to do - a micro-blogging service.