PDF (Portable Document Format) is a document that you can open and read with Adobe's free reader (http://get.adobe.com/reader/) - formerly Acrobat Reader. There are other viewers you can use as well. It's used for representing two-dimensional documents independent of the application software, hardware, and operating system. It's especially popular for documents that you can fill out online and then print. The IRS has all their forms in PDF format so you can fill them out online and then print them out. For example: http://www.irs.gov/pub/irs-pdf/fw4.pdf You can also create your own PDF documents. The other most popular document format is Microsoft Word's DOC, but you need Microsoft Office installed to view it. If you have Adobe Reader installed on your machine and you click on a PDF document (either online or already downloaded to your machine) it should open up.
Webbiejonmaster, the "New Posts" option is being screwy. Okay, well, what I was trying to do was print some graph paper because I wanted to draw a floor plan that was the right size and stuff because I'm going to be moving and I like to plan ahead. But it gave me an option to download a PDF file. And I don't like downloading things because I'm not "downloading stuff savvy" and I'm always paranoid about getting viruses and stuff. I did find something else to let me do what I wanted though, so I'm all set. Thanks for answering my question.