projectpluto.com does not use cookies. (I may revisit that someday; it could be handy if, for example, the on-line Find_Orb remembered your preferred ephemeris settings. But that won't happen soon, if at all.)
No data entered on this site is shared willingly with third parties of any sort, governmental or commercial. A search warrant or subpoena or similar legal request would be needed.
When a copy of the Guide 9.1 star charting software is ordered, your shipping and e-mail addresses and the time at which you ordered are collected. This may be used, for example, to check into why a package didn't arrive. Since payment is through PayPal, I never see your financial information.
Data entered into various forms on this site, such as the GNSS timing tools, satellite identification tool, and on-line Find_Orb, will be stored for a few days (length varies depending on how much use the site is getting; 'a few days' probably overstates matters.) I've occasionally had to dig into the logs to figure out why a service crashed, or an orbit didn't solve or an artsat wasn't identified.
I can be reached at pоç.ötŭlpťсéјôřp@otúlm. If you're a human instead of a spambot, you can probably figure out how to remove the diacritical marks...