Protection against lost
I will use Todoist professionally. It is very important to me that no entries are lost.
How are the entries protected against loss or can I back up the data further.
Ideal would be an automatic backup locally on my PC. This can be an expression in a PDF or something else
all data stored on our servers is very secure. We're using Amazon's Web Services http://aws.amazon.com/security/ , all data is backed up multiple times every day and no data has ever been lost.
Furthermore, our current mobile site http://todoist.com/m as well as our recent and upcoming iOS (and Android) apps, support HTML5-based offline storage which means, if you sync your data through the mobile site with a particular browser, it will always be accessible even if your offline. We will soon introduce HTML5-based offline storage on the whole web-app as well which will ad another level of security for your data.
Import/Export options might be introduced in the future as well.
It is imperative to me have export options. Although I trust your security at a certain level I still need to know I can take my data somewhere else if necessary. It's okay if you make it a premium feature.
we will certainly consider adding an export option in the future. You're welcome to vote for this request in our Votebox: http://todoist.com/Vote/showProposal/30/
For now, as a backup, you can use the mobile site http://todoist.com/m which can be accessed anytime even without an internet connection (after you access it online once). You can use it with a different browser than you use with the Todoist web-app and synchronize it online once in a while to see the latest state of your tasks and be able to access this data anytime.