The Big Tree is based upon Geni (Source: MyHeritage Live Oslo?)
Some tree sites are Sources (Record matches), such as Geni, WikiTree, Geneanet, Filae, and FamilySearch. Thus, building trees at these sites will improve your chances of forming Tofrs.
Accepting Smart Matches links people in trees together (also the Big Tree). Accepting record matches links people to the same source and thus can link trees together Want more Tofr's? add more data (places and dates) to ancestors, always accept correct person of smart/record matches on your ancestral line when they are "correct"
Note: Acceptance of a smart or record match doesn't require users to copy data. Not all facts need to be correct to link people in a tree. Is the person correct, then accept match. Leave match alone in doubt. Reject if person (not details are wrong)