What a marvelous question! I can see how helpful this discussion thread can be for possibly creating a new FAQ and/or "Welcome to WikiTree!" resource!
I've loved telling friends and family members about some of my favorite aspects of WikiTree, and why I now invest most of my genealogical research time working on our shared WikiTree, and my enthusiasm must be infectious, since many friends and family members have at least viewed WikiTree pages, and a few have signed up and had a look around this past year.
So here are the top three questions I've heard from newcomers to WikiTree:
(1) How can I most easily add my family tree information from my computer system to WikiTree? I've noted some people start out enthusiastic about WikiTree, but seem to hit some kind of roadblock with regard to putting in the time and effort required to verify every single profile in their tree, that oftentimes they feel they've already worked hard enough to confirm and validate.
(2) How do you update/edit WikiTree pages? There appears to be some sense of uneasiness/lack of confidence with the WikiTree newcomers regarding adding to what looks like html code on profile pages
(3) What sources are best for WikiTree, and how do you find them? Once the fore-mentioned hurdles are cleared, there remains some hesitancy regarding how best to find and cite primary sources, even once free and fairly-easy-to-use sources such as familysearch.org and FindAGrave are found.