ditto, more than happy to share, does anyone know about the terms and conditions of whichever sharing service we might end up using in relation to inadvertently handing over any usage rights to the host. Google drive for instance states.
When you upload or otherwise submit content to our Services, you give Google (and those we work with) a worldwide licence to use, host, store, reproduce, modify, create derivative works (such as those resulting from translations, adaptations or other changes that we make so that your content works better with our Services), communicate, publish, publicly perform, publicly display and distribute such content.
Dropbox is broadly similar although both issues various caveats along the lines of
The rights that you grant in this licence are for the limited purpose of operating, promoting and improving our Services, and to develop new ones.
TBH I've not really had to worry about this with the stuff that I use them for but I just want to be sure that I'm not putting somebody else's material into the hands of tax-shy corporate behemoths.