In addition, Ben Shachter, an analyst at Macquarie Securities shared some results of interviews with a panel of youg Facebook and Instagram users. He found that they all became active Instagram users within the last year, and most indicated that while the still use Facebook, they expect to use it less in the future. Part of that may be a result of a shift in their perception of the value of Facebook - less valued as direct social medium, while increasingly valued as an aggregator of all of their social connections. Many also indicated that they were turned off by some of Facebook's newer features. They found the Timeline feature, in particular, too convoluted and "creepy."
Instagram was favored by the group as the best option “to capture a moment, highlights of my day,” and, counterintuitively, since most of their Facebook friends are not on the photo-sharing service. That suggests people are looking for ways to reach smaller groups of “real” friends, with females seemingly more drawn to Instagram than males. In addition to Instagram, people are also turning to social platforms like Tumblr, Pinterest, SnapChat, and Path as Facebook replacements.As of July, Instragram had 22.7 million users - up 38% from the previous month. It's got a ways to go to match Facebook's 955 million registered users (as of July), of whom 552 million log in daily. And with Facebook's acquisition of Instagram, Facebook wins anyway.
Sources - Rival Social Apps Chip At Facebook's Dominance, OnlineMediaDaily
Instagram Gaining Griound on Facebook, OnlineMediaDaily