Excluding HTML, PDF files are probably the most popular document format on the web. Unfortunately, they’re not compact. For example, I like to download free eBooks. A quick glance at my eBook directory shows that its 75 PDF files consume about 500 megabytes. On average, that’s over 6.6 MB for each PDF file. Couldn’t I save some storage space by compressing those files?

Source: LXer – Shrink PDFs with this Linux tool