Session save files should save digests of window titles, and not the window titles themselves.  This is sufficient for matching.  Here's the reason why using plaintext is bad:

$ grep epiphany ~/.metacity/sessions/*.ms
/home/marnanel/.metacity/sessions/1139024473-10078-1512709150.ms:  <window id="117f000001000113897822400000025320007" class="Epiphany" name="epiphany" title="Inter-Client Communication Conventions Manual" role="" type="normal" stacking="2">
/home/marnanel/.metacity/sessions/1139026481-11327-4253752538.ms:  <window id="117f000001000113897822400000025320007" class="Epiphany" name="epiphany" title="Changes made to bug 141425" role="" type="normal" stacking="1">

and so on and on, listing a ton of pages I happened to be looking at when I logged out.  I can imagine that this might cause privacy issues for some.

I am currently working on a suggested first draft of refactoring the way we store session files, and in particular what file formats are most efficient and simple to parse (as partly suggested in bug 518596 and more fully in <http://blogs.gnome.org/metacity/2008/03/08/session-management/>), and I want to bear this in mind.  Changing the directory gives us an opportunity to reconsider the file format, and this is one of the problems I've been considering about the old format.

The major trouble with it is that digest algorithms were only introduced in glib 2.15 (<http://library.gnome.org/devel/glib/2.15/glib-Data-Checksums.html>), and we're currently requiring glib 2.6, which seems a heck of a jump.  Does anyone have any thoughts about whether the advantages here outweigh the disadvantages of requiring 2.15?