Can I still publish my thesis elsewhere if I publish it "closed access" with ProQuest?
Here's ProQuest's author rights agreement for the &quot;closed access&quot; option (linked to from here). As you can see, they only ask for non-exclusive publication rights. So yes, using this option would leave you free to disseminate your thesis through other avenues. In my opinion, if you can host your thesis in some kind of stable repository (e.g. one provided by your university library) for free, there's no real reason to pay ProQuest for open access publication. Of course, if you want to, or can get someone else to cover the fee, there's no harm in redundancy. However, as far as I can tell, it doesn't seem to appreciably affect discoverability through search engines.