It is very important for me to keep my files in a safe Host. I use ubuntu one because of ease of using in Ubuntu. You think is it safe enough of spying ?
closed as primarily opinion-based by user68186, Alvar, Mateo, Jorge Castro, gertvdijk Jun 30 '13 at 18:44
Many good questions generate some degree of opinion based on expert experience, but answers to this question will tend to be almost entirely based on opinions, rather than facts, references, or specific expertise. If this question can be reworded to fit the rules in the help center, please edit the question.
According to the German Wikipedia and the results of Whois and GeoIP lookups, the Ubuntu One servers are located in Great Britain, which is definitely not the worst location to have servers, since it is inside EU, meaning that there are relatively strong privacy security laws in effect, and that it's a partner country grade 2 (source) of the USA, meaning it's explicitly excluded from their systematic data theft and industrial espionage (at least, officially).
The transmission of data to the Ubuntu One servers is done using SSL, meaning that it's reasonably secure, at least if you use the web interface and check the used security certificate (the NSA and other industrial espionage agencies have the wrong to have certificates for TLDs issued, allowing Man-In-The-Middle attacks if one doesn't check the certificate used).
Nevertheless, Ubuntu One stores files unencrypted, to enable the user to publish them over it. So, if for any reason a British court decides that Ubuntu One has to give data to the police, the police will get the files and will be able to read them without problems.
Therefore, it is strongly recommended to encrypt any data before it gets uploaded to Ubuntu One (or any other cloud storage). You can either do this manually (for instance with gpg or openssl), or use an automated solution. Someone reported that he used encfs with Ubuntu One successfully.