For any link you share, the number of clicks displayed in snick.link could be different from the number of clicks you see in your social media or email accounts, like Facebook, Instagram, Mailchimp, Marketo, etc. This is because each platform measures clicks differently.
How snick.link counts clicks
When your shortened link is clicked, the click goes through snick.link to get to the destination page. What you're seeing with snick.link is the number of times a link is expanded from the short link to the long URL.
How other platforms count clicks
Other platforms and apps measure clicks using different methods, using code on their pages or trackers added to the links that you paste into their apps. For example, Google Analytics measures events on the page using Javascript.
Other things that affect click counts
Bots, applications like browser plug-ins, and spam checkers in email programs might expand a shortened link without taking a user to the destination page. For instance, if you use a browser plug-in that automatically expands short URLs, it looks a lot like a human user to an analytics program.