Places Disabled on 1.8 Branch
Places has now been disabled on the 1.8 branch. This means if you’re using a branch nightly build you need to export your Bookmarks now before updating to tomorrow’s builds, otherwise any Bookmarks you have added since Places was enabled will appear to disappear after the update (they’re still there though, you can load a Places build to view and export them).
Read the post Important Message for Branch Nightly Users - Places for more information and for instructions on how to export your bookmarks.