In the old days, vendor lock-in was on the radar of free software developers. Many systems based on Linux and BSD are used to host internet applications, so many that in fact the server side was considered safe and forces gathered to conquer the desktop. The real push towards a free desktop began 10 years ago - with KDE and GNOME being founded, bringing many powerful applications to the average users. But that’s still 10 years ago - and times have changed.
Today, many user use a free desktop to check their GMail, then tune in to some Shoutcast beats, and finally think of doing their daily backup by uploading some files to Amazon S3. At the end of the day, they did use some free client applications - but likewise they did leave precious data at proprietary service providers. When freedom and privacy are equally challenged, people should shout loudly and stop using those services. But instead, they spend their time developing more interfaces for them.
The Four Freedoms Applied to Software as a Service talks a lot about the value of data, but there are pragmatic questions about the use of a service hosted elsewhere as well. If your work or data depends on the good attitude of someone else’s server (think CDDB versus the truly-free replacement, FreeDB), are you truly free?