Just realised that the stream posting box doesn't appear on the 'Event Information' view of an event.
When you events set, as I do, to show the 'Event Information' by default then a logged in user has no idea that (s)he can contribute all your wonderful things to the 'Timeline'... do you see what I mean? It reduces the opportunity for user engagement and involvement... so shouldn't the 'stream posting box' (not sure of the right name for it.. but where people can add things to the stream) show at the top of the event info view just like it does at the top of the event timeline view.
(Going forwards my preference remains to combine the 2 views of course.. that's on Voices. People don't want to work hard to find things.. so 1 view, event info at top, stream below is the simplest way to keep EasySocial Easy!)