Ad networks on tracking sites use browser fingerprinting techniques.
The term "link39" is not a standard URL shortener like Bitly, but could be a custom redirect used in piracy networks to hide final destinations and bypass security filters. These shortened links often lead to streaming servers, file lockers, or phishing pages, and are considered a high-risk vector for malware.
The trade-off is that you must "unpack" or decompress the files on your local machine, which can take anywhere from 10 minutes to several hours depending on your CPU speed. Breaking Down the Keyword Components