There are some aspects of using Tarsnap which benefit from a longer explanation.

• What is stored in the cache directory?
• What network resources does Tarsnap require?
• How can I improve the speed of some Tarsnap operations?
• Why do I need to be careful about backing up a live filesystem snapshot?
• How can I have greater control over which files to back up?
• How can I run Tarsnap on multiple machines with the same key?
• How do I deal with partial archives?

Think something about Tarsnap is interesting enough that it should be explained here? Contact the author and let him know.