Privacy
What is kept
Your email, what your business is called, and the figures you put in: the jobs you write up -- what you cleaned, how big it was, what you charged and how long it took -- along with what your own hour is worth and what the business costs to run.
Where it is
On this server, in a folder of its own, one per business. It is hosted, so I can see it — I am not going to pretend otherwise. I look only to answer something you have asked me or to fix something.
What is never done with it
Not sold, not shared, and not used to build a benchmark other businesses can see. Nothing is ever sent to your customers.
If you would rather it stayed in your building
Say so. Waterline runs exactly the same on a computer in your office, and then none of it leaves the building.
The rest of the JTS tools
One trade each, and the same idea every time: one number you have never had, worked out from what you already know.