I figure now might be a good time to clarify that by:
[quote="scroton"]If they fit the above criteria (don't break other things, can be placed behind cvars) and you're alright with sharing them they'll probably get in to the mod proper so others that want the same things you want can have them too.[/quote]
I meant things like the existing cvars or otherwise gameplay changes or things like huds and so forth that would typically be a "mutator."
Like if someone wanted to have chaingunners fly and deal double damage, that would have a good chance of getting put in under a cvar. Or have Droplets instead of normal blood, or maybe they really want the NC-Hud. All of those could get put in without being a major undertaking, wouldn't affect people playing without them, and wouldn't impact filesize very much.

That doesn't mean that addons (like adding 4 new chaingunners and 5 new weapons, say) have no chance of getting in, but they aren't subject to the same philosophy as the listed above are, and aren't as likely to get in.

Feel free to share your addons here or in the irc though, and we'll link them in the OP for others to play.

If you're putting work into an addon with the expectation that it will get into the mod proper, it would be a really good idea to talk to Marty before continuing on it and keep him informed while working on it if he says it's okay.