Gedcom

[Wulfsige]

I have my family tree on myheritage and have uploaded it to gedcom. When I add to my tree on myheritage, do the additions get added automatically to what members of other sites can access via gedcom, or do I have to upload anew to gedcom every time I add to the tree?

[RJ_Paton]

I'm presuming you are actually referring to Gedmatch.
(A gedcom file is the saved data file used by the majority of genealogy sources to transfer information created in one program to another to enable it to be read and displayed in the same way as the original ).

If you are referring to Gedmatch then the answer is that it does not automatically update and if you need to change the tree at one source (eg MYHeritage) then it needs to be updated manually by transferring a saved version of the updated tree by means of a gedcom file.

All of the sites are seperate and operate independantly of one another. (they are mostly commercial companies out to make a profit)

[Guy Etchells]

I have my family tree on myheritage and have uploaded it to gedcom. When I add to my tree on myheritage, do the additions get added automatically to what members of other sites can access via gedcom, or do I have to upload anew to gedcom every time I add to the tree?

No each gedcom file is a time specific replica of your database file at the time you made it. If you add more ancestors, descendants, notes etc., to your family tree file you will have to make (export) an additional gedcom file to reflect those changes.
Cheers
Guy