You bring up an interesting point.
I am one who will save older versions of applications, just in case I need to go back a version or two. It also helps when I rebuild my machine (or a friend/family's machine) so I don't have to go re-download all the applications.
So, I went and looked to see what I had for Skype. I have 6 versions, and they are all pictured above. It is interesting that the last one I downloaded grew from just around 1 MB to just under 30 MB.
By the way, the filenames that I have listed are modified when I downloaded them. I believe they were all called "SkypeSetup.exe" when I originally downloaded them. I then renamed them to be SkypeSetup_versionumber.exe so I could tell them apart.
However, the current exe name is called "SkypeSetupFull.exe" when you go to download it.
It appears that Skype may have changed their install method. Before it could have been a shell that you would launch, and it would pull the rest of the install down from the web at that time. It looks now that when you download skype, you get the full install package.
--Brian