In January I published a blog post about the growth of Instagram. I hade noticed that the unique ID numbers for photos on Instagram were handed out in a serial sequence. In other words, it wasn’t very hard to calculate the growth of the service since the data was publicly available. All you had to do was a bit of digging. For example, here is photo number 400 million: http://statigr.am/viewer.php#/detail/400000000_3849764
Update: the links to Statigram no longer work
A few weeks later, on Feb 7 to be precise, Instagram changed the ID numbers from serial sequence to what looks like a random set of numbers. As of this date, the ID numbers are determined with what I believe is called a hash function (please correct me if I got this wrong). It is no longer possible to determine the volume of uploads to Instagram by simply looking at the ID numbers.
So how do I know this changed on Feb 7? Take a look at the Instagram user “boobievsjagger“. On that day, he posted this photo:
According to the first part of the unique ID, this is photo number 686,008,000. The second part of that string is the ID for that user.
Later that day he published another photo:
The first part of the ID is now replaced with 18 digits that gives us no clue to what number among the uploads this photo has. The same goes for all other images posted after Feb 7.
I predicted in my January post that Instagram would reach 1 billion uploaded photos by April this year. If you ask me, I think Instagram changed the way each photo is identified after my blog post, which was also picked up by The Next Web, among others. So now we can’t tell how fast Instagram is growing, until the company decides to tell us themselves. Let’s wait and see.
A related question is if the ID numbers for members on Instagram also will change. As it looks now, you can tell that Instagram has at least 27 million users. Here is a friend of mine that just joined: http://statigr.am/viewer.php#/user/27135093/