If you are writing a dissertation or advising someone who is, you may be interested in this post:
Why are parts of my Washington University dissertation in Google? Why is my dissertation for sale in Amazon and elsewhere? How can I remove it?
Note: In my opinion being able to find dissertations on Google and purchase them from Proquest is not a bad thing; it can be exceptionally useful in fact. But authors need to know their rights and negotiate for options that suit their needs. This is an area where some graduate students have probably not been aware of what they were choosing.