In 2011 I wondered who stopped following my Twitter account when the follower count fell. I wrote about who.unfollowed.me, which compared follower lists over time and showed who had left. It satisfied my curiosity about the reach of my posts; it did not tell me what each former follower was thinking.
Who Unfollowed Me now points users to Fedica. According to the provider, tracking starts only after you connect an account; it cannot retrieve earlier unfollows. Its current pricing also differs from the amount in my old article. Check the terms before granting access to your social account.
What does an unfollow tell you?
A name and date show that an account left. They do not explain why. Someone may change interests, leave the platform, tidy their account or simply prefer fewer posts. Do not draw sweeping conclusions from one departure. Look for patterns over time and pay attention to the reactions of people who remain engaged.
My original article also mentioned accounts that do not follow you back. That is a different measure. You may follow someone for their knowledge without expecting a reciprocal relationship. A list of one-way follows is therefore not an automatic cleanup list.
Consider the access you grant
An outside analytics tool needs to communicate with your account. Review the permissions and whether you can revoke them later. Use a service that connects through the platform's official method, and never give your password to a separate website.
My old tip remains an interesting observation about social curiosity. The more useful question, though, is not “who left?” but “what do I want to share through this account, and who finds it valuable?”.