Not sure what you mean by protection.
Nabble provides a service over which you have no control should they decide to stop running the service - the same as all the other service providers you mention.
If you want control then why not rent server space, install WordPress or any of a score of alternative blogging software platforms, then you can back up everything locally to protect your product should your current host go down.
Volunteer Helper - but recommending that users move off the platform!
Once the admin for GregHelp now deleted.