Just read Alastair Reynold's short stories "Signal to Noise" and "Cardiff Afterlife" and they contain a technology that might fit the EP universe in some campaigns. Slight spoilers. The technology is "cold calling": big supercold iron masses are placed in some quantum superposition, and randomly "dial" identical iron masses in other parallel universes. Once they achieve a "lock" the parallel labs can use this quantum link to communicate with each other. This information channel has a limited bandwidth: in the stories it was enough to run a link of a few megabytes per second at best. The parallel world contacted will be essentially 100% identical (no confederate victories, just different quantum noise). But the worlds will start to diverge after the lock. As the universes diverge from each other more and more noise creeps in, reducing the bandwidth until the lock is lost after a week or so. In the stories the bandwidth was enough to allow remote puppeteering of a body, but video calls and text messages of course work better. What use is this, beside cool physics and getting alternate football matches? Imagine that a problem exists, and the team in universe A tries one solution and the team in universe B another. If one of them succeeds they can tell the other. More importantly, if a crisis occurs in the A universe (after the lock has been achieved of course, since the previous history was identical) the investigation in A can give information to a team in universe B to investigate, who can give back intel to A. For example, if suicide terrorists strike somewhere in A, their identities can be given to B where they failed or had second thoughts. Intel from B can then be used to track down confederates in A, and so on. Using a number of cold calling devices to keep in touch with alternates a group could gain valuable intel from their alternate counterparts. It would be limited by available bandwidth, that one cannot preselect which universe one locks onto, that the link will be lost and that sometimes all alternative investigations fail. But it would still be quite powerful. This tech sounds just like it fits EP. This could be a secret of powerful groups like Ozma or the Prometheans, giving them an uncanny ability to seemingly out of nowhere figure out things (and of course, this is how TITANs and ETI *think*). Or it could be new tech that becomes the McGuffin for an adventure - everybody who understands the implications want it and want to keep it out of the hands of everybody else (except the radical Argonauts, who think information should be flowing freely between parallel worlds). One twist would be that Firewall agents are sent to stop an innocent research team on the verge of discovering the technology - Firewall doesn't want to lose its edge.