I recall seeing a suggestion for a kind of bulletin-board comms feature in Pioneer, but I don't know where. (My search fu is weak today, but I did look. Didn't find it.)
But ever since then I've been thinking about ways to add an optional multiplayer component to the game. That's a nontrivial challenge! Pioneer isn't suited for the kind of MMO play we see in Eve Online, or Star Trek Online, because of time compression and a dependence on procedurally generated stuff. However, I think there is still some room for novel sharing of experiences, especially if they aren't difficult to code. Since we can't do things like combat, the tokens passed between players would have to be bigger-grained. Things like messages, locations, possessions, etc.
There was a game called Noctis V, a very strange little exploration game not unlike Pioneer in some ways.
http://en.wikipedia.org/wiki/Noctis
http://www.gamerswithjobs.com/node/17541
It had a rudimentary multiplayer component as described below. The same idea was used by Will Wright's Spore.
For some time Alex regularly compiled a new GUIDE based on emailed submissions of players of their "Outbox" and allowed the compilation to be downloaded as an "Inbox"; the GUIDE has not been updated for several years since 2005, but since December 2008 the service has been restored again.[2] A more automatic system of "massively single-player" content sharing is used in 2008's Spore.
The first thing to consider is whether we can add such functionality without any code at all. One could do a lot with just a forum thread, as shown below.
Travel Guide - forum thread only
This is exactly what Noctis did. People explore, and contribute to a list of interesting coordinates in a forum thread. There's no competition whatsoever, it's just a way to highlight fun stuff generated by the procedural routines.
Market Reports - forum thread only
Players share prices/market information for systems they visit, so people can get an idea what is needed where. You'd think the Pioneer universe would have some kind of fast-courier service like the Pony Express in the American West, just to help traders decide what to trade.
Challenge - forum thread only, describing the challenge, and a saved game
This has already been accomplished with Brianetta's orbit challenge, so we know such things are possible. The challenger poses a challenge and others try to accomplish it, and share results in the forum thread.
Race - no code required beyond establishing a forum thread and honor system
People start a new game and fly to a system before anyone else. "Pebble lands on P Eridani A g as of 1634 10 Feb 3200", after first having flown there, that sort of thing. No provision for cheating.
Gold Rush - Same as Race
Players race to claim various star systems, and record their claims in a forum thread. This would be fine among a few players who trust each other, but this would become a documentation headache as time passed.
Star Control - Same as Gold Rush and Race
Players agree to start at different systems, and work to construct the best combat craft possible within a deadline, and claim a contested system. The combat would be handled by a kind of rock-paper-scissors, based on the ship types and known performance characteristics (gee rating, weapon/shield output, etc.). Rinse and repeat until someone meets the victory conditions. (This is a very high-level description)
Roleplaying - forum thread only
Players role play what they're doing (along with in-game time stamps) according to some pre-established rules. Could be fun, if somewhat loose.
Anyway, these are my code-free ideas at the moment. I have some minimal-code ideas, but I'll put them in another post.
EDITS: Fixed some typos.
Thanks, Robn! That's precisely where I saw it. I think the idea of messaging is great.
I wrote that wiki article. (-:
The reason for having this feature in-game, rather than on the web, is that it increases immersion. At the same time, it reduces off-topic, out-of-character chatter, because everybody who's participating is actually in the mood to play the game when they do.
Sure, some people would release an extra client that could allow people to interact with the service from outside of the game, but those people smell and aren't invited to any parties. So ner.
I was just thinking about the message/inbox thing. What if instead of just text your message contained cash or a rare piece of equipment or whatever from a friend? What if it actually had a little bit of Lua script embedded in it to do something clever on opening? (leaving security concerns aside right now).
It's interesting, but wide open to abuse. There would be no (enforceable) in-game cost to sending presents to other players, or even to oneself.