Acrobat 9, Click on Document>then Reduce Pdf Size> then will prompt to click which version or later to reduce, pick any, doesnt really matter> then pick where you want to save it, and voila. Let it reduce it, takes 1-2 minutes and voila your done !
This retains the quality but removes all the background junk that there is in PDFs. I just did a 13mb file down to 800kb file, works great !
1. From within Pages or any other application you're creating a PDF from, click on "Print" in the File pull-down menu.
2. In the Print dialog box, click on the third pull-down menu box ("Copies and Pages"). Select "ColorSync" from the pull-down menu.
3. Click on the "Quartz Filter" button and select "Reduce File Size."
4. Click "Save as PDF."
In the case of my three-page brochure, the resulting PDF was only 227KB (rather than 10MB).
Save the PDF as a .ps file in Acrobat Reader.
Open Distiller, and under Settings->Job options->Compression, specify your downsize resolution.
If you want a PDF for viewing on monitor only, downsize all graphics to 72 dpi, or 90 at most.
That will probably reduce your file quite a bit.
After setting the options, open the .ps file in Distiller, and it will spit out a much smaller PDF.
Note, that it might get the same name as the original, so make a copy of the original, so that you don't overwrite it. The process is irreversible :-)
Have you ear about DjVu? is a GNU compresion tool similar to PDF, who is rapid taking place over PDF files. Primary reason: typically DjVU files are at least 5 times smaller than PDF files for the same document, DjVU viewer is a Add-on that installs itself and you can convert wherever you want to DjVU for free.
Open the pdf in acrobat. Choose "save as" and save over the original document. And voila! The file size is smaller. If you simply choose "save" rather than "save as" the file size will remain the same.
Open your PDF, go to Print, print using "Cute PDF Writer" (yes, slyfox-ly converting your PDF into yet another PDF) and it'll somehow shrink it way down. Mine went from 9MB to 6MB. It may or may not continue to downsize the more you do each new PDF.