Awesome little service this... I got a new phone and didn't have the software to sync my motorola to get the contacts to the new phone. So I found the "sync" option on the phone, setup a (free) account with mobical, then uploaded all my contacts, calendar, tasks etc. This took minutes (including setting it up).
I then put the details into the new phone and it connected and downloaded all the details also.
I can switch it off now but think I might well keep it as a good online backup!
It depends on how trusting you are of their terms and conditions which state they won't do that, although it did occur to me. It is a very comprehensive tool which they seem to have invested a lot of time and money in, not some mickey mouse operation so I trust they don't want to throw that away by (illegally) passing my contacts on.... maybe thats naive.
While they say they wont, what happens when they get bought out? IIRC this happened with a call centre company the main parent company purchased them and all their logs and then started using this information (illegally???) To call customers. I am sick of this happening with my email address on sites thus why I have a spam email address that is checked once a week and the main one for propper correspondance.