FWIW, I find it useful to "print" a PDF directly from a webpage showing a miles offer. The PDF will contain an exact likeness of the printer output (with browser time stamp, etc.), but can be used for electronic communications with a customer service agent. It's helpful to attach this kind of thing to every e-mail correspondence, as the PDF files are usually relatively small.

I use the freeware pdf995 package (available at www.pdf995.com).

(P.S. I'm not hawking this thing - I just use the software myself. At $0, the price is right, esp. compared to Acrobat at $300 or whatever.)