There is a complete Luminotes privacy policy on the subject, so please check that out if you're interested in how Luminotes protects your privacy. The basic gist is that the contents of your wiki won't be read by Luminotes developers or shared with anyone. But read the full policy for details.
What about backups?The Luminotes database is fully backed up every day, and you can even download the entire contents of your wiki by clicking "download as html" whenever you want.
Does this cost me anything?Use of your Luminotes personal wiki is completely free. You also have the option of upgrading your Luminotes account to get notebook sharing features and additional storage space for a reasonable subscription fee. But the features you're using now will always remain free.
What does Luminotes run on?I'll be happy to answer it. Check out my contact info for details.