Avsim have a fairly unfriendly politic for newcomers : register or go away. I can't find an other example of a website who limit acess to his content that way (except of course membership based websites). So many people will not sign up because they can't see what is behind the register wall.
I post stuff here because I think my work may interest some simmers, but most of these people are more in a "wait and see" mood. Some of them show more interest but only a few have really contributed to the project (the World2Xplane library creator, for example). That's the reason why I mostly post screenshots in Avsim, to keep people interested in some way, hoping that one day maybe a talented and motivated person will jump into outerra and start making planes for it.
However, people give a good reception, majority of them have understood that Outerra is a slow progress project, but not a vaporware (I have not see such reactions since a long time, thanks to your active lobbying
). My posts on the screenshot forum are welcomed with a really positive feedback, maybe we should gather cool pictures and post them once every month