PdfCompress reduces the size of PDF files.
!! Compression is file-specific, there are files that systematically cannot be compressed further. So wether it works for your files can only be determined by running the actual app with your actual files!!
If you need to decrease the size of a PDF for e-mailing or posting on the web, just drop it onto PdfCompress and it will create a copy of your file that can often be 10 times smaller.
PdfCompress achieves this by removing data from the file that is not needed for display and squeezing displayed data down to a more compact representation, where possible. PdfCompress automatically chooses the most appropriate settings for a given file, but expert users can influence the trade-offs using a few preferences and a simple quality/compression slider.