Uploading online all Data used in thesis?
In general I think this is a good idea, but it might depend on your area. This way others can verify your method and compare it to yours. At least this is how it is used in for example Computer Vision and Machine Learning.

Some examples:


Online image database (University of Edinburgh
Different data sets of the University of Texas
Computer Vision test images (Carnegie Mellon University)
Microsoft Research Image understanding


Some theses with a dataset published:


Doug Downey's PhD thesis
Soo Ling Lims' PhD thesis
Toine Borgers' PhD thesis


Professor S. Rüger from the Open University UK, wrote in How to write a good PhD thesis and survive the viva (for a PhD in the computing subject):


  Some value in a PhD thesis is drawn from careful
  experimental design. It is best practice to only change one parameter at a time; to use datasets that are publicly available or at least make datasets available; to describe experiments in a way so that they are reproducible; and, particularly in Computing, to set up experiments in
  an automated batch fashion.


You however have to make sure that you are allowed to (re)publish the data on your web without violating any copyrights (even if it can be downloaded for free), otherwise you can just link to the external data set.

Edit: also see this question about Publicly Available Datasets.