https://news.ycombinator.com/item?id=14245119
If you encode it with this shortener, you get this 35 character string:
mNb:w9iIp7u8di:AKB2xrPUVYUFhfRUWHwA
Assuming you were using this string as a key in a shortening service like this:
https://short.url/mNb:w9iIp7u8di:AKB2xrPUVYUFhfRUWHwA
... you'd end up with a url longer than the original url! So it's not technically a url shortener :)