Thanks a lot for the comment. You are right to remind us that our phones are partially under control of other companies. Nevertheless, I don’t agree with you that smartphones are more under control than other phones. The ability to download third-party applications allows us to do many things that are beyond the control of the device vendor and operator.

Also, the meaning I intended for “personal” was more in the range of “the closest device to our person”, rather than “controlled by me”. Somehow, our phone is personal a bit like our Facebook account is personal: it is closely linked to our person, even though our control over it control is at best dubious.

The “root of trust” issue also is very interesting. Today, with Facebook Connect allows many people to use their Facebook cerdentials as root of trust. The mobile phone can at least add a hardware part to it, like 2-factor authentication. Now, I would agree with you that I may prefer a “root of trust” provided by a third-party application, itself controlled by an entity I trust. However, I am afraid that this may be a side effect of our geekitude.

The SIM on my phone gives some control to the phone operator, the smarter the phone, the more control the licence gives to the vendor.

One cannot use an iphone, without accepting itunes licence, then itms licence, which give many rights to apple.

Personnally I cannot use as root of trust a device I do not fully control, and that other may modify as they wish (see amazon removing ebooks from kindles).