Yep. For this exact reason. I trust facebook about as much as I trust any other massive, sinister advertising company.

I am already subject to lockin purely because of the social networking aspect - all my friends use it. Why would I want to lock myself in further voluntarily?

And before anyone points out that google is also a massive sinister advertising company, they have shown their commitment to data portability in a way that I presently find satisfactory. FB go to lengths to prevent data portability.