The problem with any of those clouds is that we do not know who else has access to the files we store in it and how those people use those informations we stored.
As Google is mentioned: Google is an USA company and has to follow US laws. What does this mean? Google has to store what ever is posted in its clouds for ever. Google is obliged to give access to those data to any related goverment organizations which are in charge of what ever they call security for what ever reason. Those organisations can when ever they feel have accesss to all of those stored data.
Other, not legal organisations on the other hand hack such clouds, as seen in the past more then once. After the hack was detected and the details where published how it was done, it really shows that some of those cloud providers really give a **** about the security of there members.
Coming to an other company to expand the storages problem:
Skype for example is an other company which stores every call you do with it for the rest of the time.
If now some body want to have access to certain information in a short time, no problem. Do not think that it is a problem to scann Millions of TB stored any where, as the technology already exists to do so.
I am clear that we are not criminals, but I am also clear that privacy with such laws has gone. Each country has different laws and each country has different reasons for the existig laws.
So it is your choice what you want to do or how you want to handle those tools we can use in the internet. It is you who is a growing up and it is you who have to be clear about the risk you face with all those free tools, as there is at the end no free lunch from such companies.
Take care / DanPickUp