I had so much fun reading and contributing to Orion's Arm when it first started. It still has some of the best SF world building I've ever enjoyed. I'd love to see more wide-open shared world fiction out there. SCP is a great example too as gary_0 pointed out.
Been a fan of this for many years. Its likely the source of my fascination with "active structures" from reading far too much about "dynamic compression members".<p>I really thought it would be cool to build a small scale prototype before I looked at the physics more closely and realised how <i>genuinely hard</i> it is to build the turnaround magnets whatever else you use to bend the "mass stream" back around to the other direction. Still think its cool, but I realised its way beyond what I can possibly build myself with some ball bearings, magnets, and capacitors and electronics like the guys making coilguns use... its way more difficult than that haha.
I wish the Internet was exclusively this sort of thing. You know, dork stuff.<p>The other examples of this kind of community worldbuilding I can think of are the SCP Foundation[0] and The Elemenstor Saga[1], although I suspect there may be many others out there in the imaginary digital multiverse.<p>[0] <a href="https://scp-wiki.wikidot.com/" rel="nofollow">https://scp-wiki.wikidot.com/</a>
[1] <a href="http://elothtes.pbworks.com/w/page/18807121/FrontPage" rel="nofollow">http://elothtes.pbworks.com/w/page/18807121/FrontPage</a>
I really enjoy Orion's Arm! There's a substantial variation in quality depending on who is writing and how much investment's been put into a given corner of the site.<p>I appreciate its outlook a lot, overall - that the future involves <i>change</i>, but not necessarily <i>destruction</i>. It's much more hopeful than a lot of science-fiction tends to be now.