Isn't this one of the apps that take all your contacts from your device and upload them to a remote server? Since I have many non-contact entries in my address book (e.g. a contact card with DOB's, passport numbers, etc.), I'm reluctant to use such an app since it would indiscriminately take all this personal information and store it on a remote server.

I stick with Skype b/c basically, by logging in with a distinct login/password (as opposed to a MS ID linked to my other MS programs and accounts) and saving only limited information in Skype's address book, I'm limited the amount of data Skype would have and could take and save.