FB certainly can grow like GOOG. It took GOOG about 8 years to grow to where it is now and on comparible caps FB could do the same. I think there is a good possibility if FB executes correctly it could be at $100 in 6 tp 7 years which would put it on par with GOOG. Right now, however, there is a lot between 100 and where FB is right now.
I think it is duplicating GOOGLE's success.....The instagram purchase was akin to the Youtube purchase by google. The advertising dollars will flow into instagram once they pull the advertising switch as the user base is still growing exponentially and they want to max out on the users before moving it to advertisers this year.