Up is a service that keeps files stored depending on their popularity.
File storage times are one week from when they were last accessed. Or one week since they were uploaded if they're never accessed.
Meaning that if you upload a file on December 10th and someone accesses that file on the 13th, we won't delete the file until the 20th. If someone also fetched the file on the 17th, your file will stay until December 25th.
In a similar fashion; if you upload a file on December 3rd and send it to someone, then the file is never accessed again. It will be deleted on the 10th.
Even though I personally only do it to limit the server costs and keep the site running fast.
Up was a file sharing service that ran from late 2015 into mid-2017. It was under a different name, and was anonymous and logless. This has changed.
Currently using this ***borrowed*** codebase, thanks to the author.
Autumn 2017, Up returned, for what purpose.
It now uses a database (SQLite counts okay, don't hate me), it has been rewritten from scratch using Python, it's multi-threaded, it rocks. Resource usage is approximately one fourth that of the old site - while also being slower, but how the file names are generated were changed and obviously, the files are removed if not accessed for a week.