Joyce....you are just starting out.......and I expect that your profiles are coded 'private' and you are working close to home......when you get further out from your immediate family....beyond the point where Geni allows 'private' profiles you will encounter the BIG TREE of profiles that are 'public'......they are those that you find in history books, on Wikipedia, in Town Histories, on Find a Grave (FAG) and are also on MyHeritage (MH).....these profiles are often co-managed by multiple Geni users.....since they share some of the same people in their ancestry..
They usually can be confirmed by the above-named sources as well as through familysearch (the LDS site from the Mormon records) which is FREE ....this includes census data, many death, birth and marriage records, many draft registration records, etc....
In most of these instances it is wisest to 'agree' with the multi-managed profiles regarding the facts UNLESS you find info that contradicts some basic fact....at which time it is not only nice to ask for their opinion, it also saves making errors which confuse the situation less likely......so THEN you ask...
Please continue to ask questions as you get used to manuevering on Geni....and dont forget to utilize the 'help' and other information that is at the bottom of EVERY page (including this one)....
I dont believe that many of us are actually out to trace every person that is or ever was on the earth, just track our own particular ancestors....so I would call it the BIG tree rather than the WORLD tree...(it doesn't quite seem so never-ending).
You can collaborate with people who you find on discussions or who are working the same areas you are interested in....without necessarily being related.......if you like how they work and are searching the same older profiles...
And NEVER feel bad about asking questions.....I started out not knowing what a URL was...
Any name (whether a Geni member or name on a profile) can be accessed by clicking it.....so you can ask a Geni member a question or go from one profile to another in profile view.
It's really neat once you get used to it.