There is a cost to free apps. While it is great to have free email, online storage, note taking, and more we need to remember that we are giving up privacy.
Without even realizing it think of how much information can be contained in your email. Items such as bank balances, past dues, and medical information.
In many cases it is worth it to actually pay a small amount for a service where you can support a small company instead of handing your data over for mining by corporate giants.
Before choosing to hand over your information consider for a moment the cost of that privacy.