Instagram is one of the most popular image sharing service. Initially, this service was available only for iPhone users, but earlier this year it was available for Android as well. Instagram allows you to quickly take photos using your mobile phone camera and then apply filters and upload it on your account. You can also share photos to social networks. Instagram also rolled out a web interface for profiles. Just like Twitter, you can follow users on Instagram and view the photos shared by users. At any point of time, you can unfollow them as well. In case you want to find out who unfollowed you on Instagram, you can use the free web service Unfollowgram.
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You need to login with your Instagram account and authorize the service to access your profile. The service has 5 tabs to see details about your followers.
You can check who unfollowed you, who does not follow you back, who you do not follow, your followers and people whom you follow.
You can refresh the service anytime to see changes to your account.
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You can also follow or unfollow any user using the service. Clicking on any particular user will lead to their Instagram web profile.