Excluding HTML, PDF files are probably the most popular document format on the web. Unfortunately, they're not compact.
Couldn't I save some storage space by compressing those files? What if I want to send a bundle of them through email? Or host them for download on a website? The transmission would be faster if these files were made smaller. This article shows a simple way to reduce PDF file size. The benefit is that it shrinks your PDFs transparently without altering the data content in any way. Plus, you can also compact many PDF files with a single command.
See Shrink PDFs with this Linux tool
Minuimus is an open source tool used to reduce PDF storage space by 10% to 20% without altering the data.