General chat
The game often feels like a very empty and lonely place without a general/trade chat. To me, not having a general chat takes the MMO out or MMORPG. I'd love it if there were a general/trade chat in the game so I could easily find other people to group with and sell/buy/trade items. Right now, I basically friend everyone I see in the game so I can find people to group with, but it probably makes me look like a little bit like a crazy person (I'm Carlsagan, Derp, and Rose, btw). Sure, general/trade chats are often prime spots for trolling and other annoyances, but there's usually the option to /leave and /ignore.
Shoebox, who let you out of /v/?!
I think it feels lonely because the population is super small right now. After release there will be a lot of people. Too many people to make a global chat feasible in my opinion.

I let myself out of /v/ because it sucks.
A global chat doesn't seem like a very good idea. Opt-in channels would be nice however.

We've talked before about having general chat being per town. What do you guys think of that?
Personally, I think the problem will solve itself on release. There'll be more players than just the beta testers, and as a result there'll be a lot of places to just gather around and chat with other active folks.

Guild Wars don't have global chat and it seems to work out fine.
Per town? Meh.
Per scene. Definitely.
I haven't played Guild Wars, so unfortunately I don't have an educated opinion of what it's like. The MMOs I've played in the last year - World of Warcraft, Lord of the Rings Online, Warhammer Online, and Dungeons and Dragons Online either had a global-city chat or chat channels. I don't know how much Spiral Knights is following in the footsteps of Puzzle Pirates and I'm pretty sure Puzzle Pirates doesn't have a global chat, either. I'm not certain though, I couldn't ever get into Puzzle Pirates.
Spiral Knights is, after all, a game that encourages you to be social by playing with other people. Having the option to jump in a gate with a group that's already playing is awesome (though I do wish you could see whose group you'd be jumping into, just in case you've had a bad experience with the players). But right now, the game feels very disconnected and lonely in many ways. There's no easy way to trade, sell, or buy goods except for the forums or randomly asking people (which can be weird) or finding a group of new people to adventure with. There are guilds now, of course. But I don't like the idea of limiting myself to a small clique and only adventuring with a certain group of people. Ultimately, one of the reasons I like MMOs is for the social aspect.
Derp.

The game feels empty because it is empty.
I don't see what's so hard to understand about that.
Guild Wars works because they have specific vendors for items that are all player supplied and bought.
Armor Dyes are sold through a Dye Trader, Rare Materials are sold through the Rare Material trader, there are no player based equipment traders, only weapon and armor crafters.
There's no confusion with the systems, the chat is simple enough, there is a global trade chat and nobody uses it, because there is no use for it.
Global Chat, as it is now, would just be blocks of annoying text, just like loot messages.
It serves no purpose, whatsoever.
There are systems they could implement that would make it that much better.
I don't know how empty the game actually is, it's impossible for me to tell. I know there have been a couple threads in the announcements section that mention lots more invites going out, and I've been giving out invites whenever I get them. But the amount of players doesn't seem to be getting larger, it feels the same as a couple weeks ago.
I can only assume there will be some sort of auction house/trading post in the game in the future, so a "trade channel" wouldn't be the most important channel to have in the game. But I think *anything* that encourages players to be social is a good thing. 100 energy a day is incredibly limiting, you can play 10 gates a day, granted that you don't die or do any crafting - which is about an hour of your time. What's there to do in game after that? Uh... Not much, so give more outlets for people to socialize in game and stick around longer. This doesn't necessarily mean that SK will turn into Barrens chat, though. I've left chat channels and ignored several people in previous games, but having them there has always been incredibly beneficial to me as a player.
I think I like the idea of having a chat channel per town.
The Bazaar, however, should probably get its own channel, which would function as trade chat. People rarely go there for the vendors, so making it a place to trade with players would be great. It would also keep trade spam out of other areas if there's some indication that the Bazaar is the place to go for trading. Alternatively, each town could just have a general and a trade channel.
Having a separate tab (or separate window) for general and trade chat is kind of a must.
The biggest thing I find confusing is knowing who can hear you when you say something. In the clockworks it's different than in a town. I think it should be closer to the same. It drives me crazy that I can't talk with a group of people as we all run around the arcade checking out the gate configurations -- the knights on the end always get too far away and miss what's being said.
On the other hand, I found that things seemed to get a lot more social as soon as I started using /guild chats. It's amazing how the presence of 2 or 3 other people that you can talk with suddenly makes the world feel more populated.
I'm in support of broader chats and channels.
By invitation chat channels would be nice. The chat host could invite as many people as wanted into the chat. I don't like that the chat has been changed to town-wide, and I'm fairly certain they will change that back once the game goes more public. Sure, it works for now, but in an earlier alpha test, when we had a lot of people on here at once, the chatter got pretty intense, even with it being limited to small geographic areas. Would the game programming allow chat circles similar to YPP? That would be an easy way to ascertain who was listening in to a particular convo. I wish /tell was easier to use. If the person isn't visible, it's a pain to have to retype her name over and over for every remark. I like the idea of a dropdown for tells, with the objects of the last several tells listed. I also like the idea of having our own spaces/cubbies/houses/gardens for decorating/entertaining friends.
Im torn on a global chat. On one hand, I have seen plenty in games where any general chat populated by enough people becomes just garbage as far as "chatting" goes. On the other hand they serve decently as a advertising/matching tool. IE its kinda hard to LFG in SK as it stands cause there is no way to advertise yourself as LFG. In many games that would be accomplished in a global chat channel either general or LFG specific. YPP! dosen't have a genreal channel for such, but instead utilizes the notice board, which fills the same need. I guess the ability to join parties in progress kind fills that niche, but honestly I feel uncomfortable just jumping into somone else's party un-announced.
I guess that I have just gotten used to more flexible game chat systems, tabbed systems, which let you have the more spammy channels (like a global), but that you can ignore them when you dont want or care to see them. Eve-O and Age of Conan both, despite any other problems with the game, have fairly decent chat systems. Totally aside, another chat system feature both of those have that I would love to see in SK is the ability to drag and drop inventory into chat, so as to let others look at the properties of an item, either pre trade, or just for show-off purposes.
One thing WoW does very well is opt-in channels, player-creatable channels. It's a system that both encourages socialization, but also allows people to avoid chat if they wish to.
Barrens Chat, Barrens Chat everywhere.