Important Update, July 7, 2011:
Since I wrote this review in 2005, PrimoPDF has changed owners. NitroPDF, the new owners, decided to include a borderline adware component called "OpenCandy" in the install program.
Previous versions of OpenCandy were considered adware by major anti-virus software dubbing it, "Adware:Win32/OpenCandy." The newer version in PrimoPDF does not set off most virus checkers. 
The OpenCandy folks adamantly defend their advertising software, claiming the anti-virus community misunderstood them. Their critics aren't buying it.
Here's what the version of OpenCandy found in PrimoPDF does:
- Retrieves a list of additional software that OpenCandy thinks you might like (and they are paid for) from their server
- Scans your system for already installed programs
- Recommends a program that isn't installed on your computer. When I tested it, OpenCandy recommended I install the AOL toolbar.
- Reports back to OpenCandy server which of the software was suitable for your system 
They claim not to store any personally identifiable information. They only collect "anonymous statistics" according to their "Your Privacy" page.
 I tested the OpenCandy-laced PrimoPDF install myself and scanned with Avast and Ad-Aware. I got no warnings. Does that make me feel more comfortable recommending it to you, the Knowzy reader? Not particularly.
 
Original Review
Think of it as the poor-man's Adobe										Acrobat. Create your own PDF files from										any Windows program that is capable of										printing. PrimoPDF is free and does an										excellent job of creating PDF										files from web pages, Word documents and										virtually any other file format. If your										PDF creation needs are modest, PrimoPDF										may save you the $300 or more you would										normally spend on Adobe Acrobat. 
 
How It Works
PrimoPDF acts like a printer on your										Windows system. Simply open the										document, web page or file in its normal										program and select the "Print" command. PrimoPDF										intercepts the program's output and asks										you where to save the PDF. After it is										finished, your new PDF is displayed										automatically.
 
What PrimoPDF Can Do
PrimoPDF implements a great number of										features that the PDF format offers.										Here are the highlights:
- Convert Almost Any File											Format or Web Page to PDFIf you can print the file, you											can convert it to an Adobe Acrobat											PDF. Just select PrimoPDF as your											printer when printing. 
- Password Protect and Encrypt your										Converted PDF FilesYou can optionally protect your PDF										files with a password. The password will										be used to encrypt the contents using a										40-bit (strong) or 128-bit (very strong)										key. 
- Prevent Copying, Editing and											PrintingPrimoPDF allows you to lock down											your PDF files. You can tell it to											disallow your recipients from copy											and paste operations. You can											prevent printing. You can even limit											your recipient's ability to edit the											PDF. In short, with PrimoPDF you can											be a real tightwad with your											content! 
- Populate the Subtler DetailsPDF files have fields such as title,											keywords, author and subject. These											are viewable in Adobe Acrobat Reader											by selecting the "Summary" menu item											under the File - Document Properties											menu. PrimoPDF allows you to fill in											these often forgotten about fields.  
What PrimoPDF Can Not Do
PrimoPDF does so much, you might										think there is no need for the										traditional, expensive software used to										create PDF files, namely Adobe Acrobat										and Adobe Illustrator. But PrimoPDF does										have some serious limitations. Here are										the big ones:
- Cannot Edit PDF FilesYou cannot make changes directly to											your PDF with PrimoPDF. If you need to											change something in your document,											you must make the change in the											original document and then convert											it to a PDF again.This process can											be cumbersome. Even a simple											document change requires several steps to											carry over that change to the PDF. 
- Doesn't Do FormsYou may have come across PDFs have											places to fill in information. For											example, the IRS has all of their											tax forms in a PDF format where you											can type in your information and											then print it out. PrimoPDF doesn't											have this capability, unfortunately.											You have to look to Adobe Acrobat											for this.