It is possible to set the settings set on your site to allow members to invite other members. To do so, go into My Family > Settings > General. Under the Administration tab, the third line is 'allow members to invite othre members to this site'
It is possible to have more than one webmaster for a site. The webmaster/creator of a site is the person who created the family site but another member can also be promoted by the original webmaster to webmaster status. He will have the same privileges as the original webmaster, except the ability to demote the original webmaster. The Webmaster has the most privileges.
To see the list of members that you have invited, go into Home > Address book. There you will find a list of the people that you have invited. You can look at those peoples profiles, promote their statuses, or remove them by clicking on one of the options on the right of each person.
if there are multiple web masters and they are in different parts of the world, do they not need to share the same source repository prior to publishing their respective changes? If joe in new zealand adds dates and other information and bob in paris does the same, will this not potentially reverse engineer each other changes when they publish?
can the site be updated using the standard web based logon or does the downloadable tool always have to be used?