Other than being the throwaway carrot to make technomancers equivalent to mages, what are the Resonance Realms? What can you do there? Why would you even want to go there? Are they just some special chat-room for the submerged?

I don't think so. I don't think you're likely to meet other technomancers in the resonance realms. They're the meta-planes of the matrix. Technomancers meet sprites there and experience a lot of wierd, unexplainable stuff that's proof to the player that their character is someone mysterious and interesting. Doesn't have to mean anything yet, just give them a acid trip adventure to keep the player guessing until we actually know something about the technos.

Oh, that's easy.

Its brain-damage.

It's where your appliances go when they break.

DEUS new Home/Prison

They may be of no interest to regualar deckers but a sourceof potential to TechnoMancers and old Otoku.

Speaking of weird places to go, what to metaplanes do? Seriously.

As much as anything Resonance Realms and Dissonance Pools read to me as a state of mind that your persona symbolicly enters into.

EDIT I suppose that could be seen as brain damage, Blackhat.

What do metaplanes do? They mostly just exist. Each is the native plane of a type of spirit or totem/mentor spirit. Because they are separate from the physical world it is open to speculation what constitutes this existance.

So in that aspect metaplanes are similar to Resonance Realms. But it is making a huge unwarrented leap to equate the two based solely on that superfical similarity.

What do they do game-wise? Do they let you summon spirits more easily?

To my knowledge, there have not been any rules for resonance realms in the previous editions yet (I´m sure they will be included in the unwired matrix sb).

Metaplanes had rules since first edition grimoir (or at least since 2nd Ed). Mages would undergo Qests on metaplanes, to get inspiration for metatechniques and new spell formulas, get a discount at spells or initiation, learn the true name of a free spirit, so that it could be enslaved or permanently destroyed, and it was nesecery in 2nd Edition to summon great spirits (more potent versions of the common spirits) via the invocation metamagical technique.