Web services used on your computer, smartphone, tablets (and other devices)are usually hosted on the “cloud”: servers spread across the planet, that host not only your data (emails, pictures, files, etc.), but also the application code.<br /> For your data, this raises the issue of sustainability (what would become of your files if Dropbox were to close tomorrow?) and of your ability to switch easily between services (how would you recover your data from Facebook or Picasa and import it, with all the adjoining comments, into another service?). <br /> For applications, this means that <strong>you are completely at the mercy of your service provider</strong> when it comes to proliferation of advertisements, changes to the user interface, etc., and that you have hardly any control over the way an application works. It is a “black box” that can exhibit malicious behaviour (sending spam SMS without your knowledge, executing malicious code, and so on).<br /> In short, these companies trap us in gilded cages: gilded yes, but cages nonetheless!