There is an additional problem (over and above privacy concerns) with putting all your eggs in one basket that is not mentioned - namely if you are cut off from the service for 1 reason or another. This can happen because you do something on 1 of the many services that goes against the TOS and you get cut off from all services. There are other reasons of course: The site could go down, the suite of services may be vulnerable to a tailored malware attack etc.