Indeed there is an annual fee for ANY number that is ported to MagicJack. I just found this out by looking at my numbers online. You'll see there is a status for the device and a status for the number. I noticed that my number expired much sooner than my device.
I chatted with MJ and they said that I "agreed" to an annual fee of $9.99, which I did not. In any event, it the middle of the "Terms of Service", under "Incoming Calls", there is a blurb about you MAY be charged an annual fee.
It's crazy that they can get away with that. I checked the FAQs about number porting and it only mentions the on-time transfer fee, nothing about a recurring fee.
I don't really want to complain too much, as the service is still really cheap, but this is a really shady way to do this.......