CDF files

[potterfan3]

What software do I need to open a CDF file?

[ACtheTROLL]

Where did you get it/them?

see
http://filext.com/file-extension/CDF
http://www.fileinfo.net/extension/cdf

not a common extension

[Buenchico]

If I read this information correctly, a CDF file (or, at least the type of CDF file referred to on this Wikipedia page) is used to define a website's content and structure. So, it can only be used in conjunction with web content, which must be viewed with with a pre-IE7 browser.

I would assume that the actual content of the file could be examined by opening it with any text editor, such as Notepad:
http://en.wikipedia.org/wiki/Channel_Definitio n_Format

Chris