AppData only tracks users who are logged into Instagram through Facebook. You don't have to log in through Facebook to use Instagram. As a result, the AppData results are only a portion of Instagram's overall usage. Therefore, the absolute numbers AppData reports are meaningless. However, the trends are interesting.
And as you can see, there was strange drop on Christmas day.
The New York Post is blaming Instagram's change in terms of service for the drop. That doesn't make sense since the terms of service flap started on December 17, and ended three days later. AppData updates its stats on a daily basis.
But, AppData tells the Post, "[We are] pretty sure the decline in Instagram users was due to the terms of service announcement."
We've emailed Facebook, which owns Instagram, and AppData for comment. If we get anything back from them, we'll update this post.
We have no explanation for the drop. (Personally, I was using Instagram more around Christmas, and so were my friends.)
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