To the best of my knowledge Plotto is "off the web", used to be www.plotto.com and <<just deleted the email addy here Brad .. LT>> . The snailmail is:
Barry Tucker, PLOTTO, P.O.Box 217, New South Wales, Australia 2011 - don't know if that works.
The info that Brad posted is correct .. that's the guy. He used to post here some times quite a while back. Personally I could never understand anything about his system but that is probably just me??
The site is definitally gone and is now a domain up for sale.