Is it possible to access your Tagsistant tagged files from everywhere, using a cloud service?

The answer is: yes! There are many file synchronization services around, but the story remains the same. Suppose you have a local folder called cloud/ which is synchronized with an external repository on all your devices. To use the cloud service, all you have to do is save your repository under that folder and use the SQLite backend, like in:

$ tagsistant --repository=cloud/tagsistant/ --db=sqlite3 ~/myfiles

Just remember to never mount Tagsistant under your synchronized folder, like in cloud/myfiles/! This will lead to an infinite recursion under the tags/ directory because synchronization software will start scanning Tagsistant mountpoint to synchronize it, but the tags/ directory is endless.