If you use Caustic on Windows and also use Dropbox:
I recently discovered a simple Windows program called Dropboxifier that allows you to sync Dropbox to folders located anywhere on your PC - they don't need to be in your Dropbox root folder. It's worth checking out. I use it to automatically sync Caustic's default Windows folder (under "My Documents") with a Caustic folder I have on Dropbox. Any changes I make to a song, any new preset I create - it's all mirrored on Dropbox (almost immediately). From there I can open them in Caustic on my mobile devices.
Likewise, this setup allows me to do things like upload .wav file recordings (say, from my iPhone) to the Caustic>Samples folder on Dropbox, and when I run Caustic on my PC, those files will be accessible from the default Caustic>Samples local folder. Pretty handy.
Dropboxifier home page: http://dropboxifier.codeplex.com/
A nice walk-though of how to set up Dropboxifier: http://www.makeuseof.com/tag/easily-synchronize-programs-settings-dropboxifier-windows/
If you regularly use Dropbox, you'll probably find plenty of other practical uses for this program. Apparently it works with other online storage too (SkyDrive, Google Drive, etc). If you decide to use it, please read the instructions carefully and back up your files first. It's been working flawlessly for me. Maybe other Caustic users will find it useful too.