Thanks for reminding me of Lisa's question.
The short answer is, I don't know.
For my part, I was kept in the dark for much of the project.
I didn't know of Char's involvement until after the fact, when the show was originally aired.
My guess would be that there was some collaboration between Char, HD, and the researchers in Cazenovia, NY.
An easy guess because several years prior I posted on the Madison county message board inquiring about my Stevensons.
So, it is easy for me to see how my name came up once they got my 2nd great grandfather's name.
'In the beginning was Alta Vista; then came 'Google'! lol
What we need to do next is ask Char!
"Guided by the Ancestors"