Sync Firefox Bookmarks using Dropbox

This solution uses a couple of the behind-the-scenes configuration options available in Firefox and the magic of the cloud via Dropbox.

1. Install Dropbox (I am sure other cloud-based sync services will work but this is my preference). Ensure that you note the location of your local Dropbox folder, this will be important later.
2. Navigate to your Dropbox folder and create a new folder titled: FirefoxBookmarks (or whatever, as long as it makes sense to you).
3. Launch Firefox. In the address bar, type about:config then press Enter. If prompted, click: I'll be careful....
4. Scroll to: browser.bookmarks.autoExportHTML. This preference is set to false by default. To change this item, simply right-click it then click: Toggle.The value should now say: true. This will ensure that each time you close Firefox (assuming a bookmark change has taken place during that browser session) a bookmarks.html file will be written.
5. You will now need to add a new preference. To do so, simply right-click any of the other preferences then select: New > String.
6. In the field provided, type: browser.bookmarks.file then press: Enter.
7. Double-click: browser.bookmarks.file.
8. In the field provided, type the full path to your FirefoxBookmarks folder (if that is indeed what you named it) followed by: /bookmarks.html. For my installation (Ubuntu), it looks like: /home/mike/Dropbox/FirefoxBookmarks/bookmarks.html
9.  Close Firefox and open your Dropbox folder. You should see the bookmarks.html file. Since any file you save in the Dropbox directory is automatically synchronized to your Dropbox account, you can now access your bookmarks from any Firefox installation by following these same steps. Note: If the bookmarks.html file is not created the first time, it may be due to the fact that no real change actually occurred to your Firefox bookmarks. Fix this by simply adding, deleting, or updating a bookmark from within Firefox (Bookmarks > Organize Bookmarks). Close Firefox again and all should go as planned.