Thanks for the spelling lesson.. yet I am not sure if i understand the reference for coming back multiple times and a potential triggering of registration? Is that referring to the creation of a website, and attempts at monetization? because there are a lot of bitcoin related sites that allow playing around and manipulating of data, but no need to register. Or are you referring to google spreadsheets?
I was referring to the fact that the user could have her inputs saved on the chart upon returning to the webpage. But @bitmover did a very good job storing the data in the browser cache, which is a great privacy-related feature.
So, no need to register.