DON'T READ IF YOU WANT TO FIGURE IT OUT YOURSELF...
I first started thinking that the codes were some sort of UUENCODE (i.e. base64), but these didn't produce much (not enough characters). Then I started thinking about the URL comment and the short length of the codes and the fact that they had no capitalization
(a requirement of the encoding process). Then I heard the "tiny" phrase and then realized that your were referring to TINYURL URLs. Next, looks at what the URLS were and put them on two different tabs of IE 7 and flipped between them. I saw there was a
difference and thought this might be an XOR. Starting looking for graphic code to do the subtraction and found:
http://homepages.inf.ed.ac.uk/rbf/HIPR2/xordemo.htm and was able to "kind of" see the text, but not enough to read it (ARGGHHH!). Then found a C# program:
http://www.codersource.net/csharp_image_processing_xor.aspx But, the EXE embedded in the project was broken (double ARGGGHHH!). Then decided to load the project in VS2008, compile it
and try it out. So far, so good, got the program to run in the debugger, but the XOR image did not fit in the window. Fortunately, I have a VERY large monitor and after maximizing got the message. Next, went to Google, searched the PDC site for the date
("17") and...the answer.