Since his introduction in Arrow, Prometheus has been an extremely mysterious villain. He is completely original and therefore we can't even find clues in the comics to help us better understand him. While I do think it is obvious who Prometheus is, it is still very unclear how he operates and what his true intentions are.
If you think about it, Prometheus has been able to pull off some truly impressive stunts throughout the show, especially for a guy that appears to be largely doing it alone. I'm referring of course to his ability to tinker with the lights in room, his constant awareness of everything that's going, and his extensive knowledge of Team Arrow. Obviously, he now has Evelyn Sharp in his court (or does he? Maybe she will double cross him). She is clearly his largest source of intel on Team Arrow, but it seems that he might have someone else helping him out — a tech person of sorts.
About 40 seconds into that video, the door opens. As Oliver enters, the phone rings. The only feasible way that Prometheus could pull that off is if he had a Felicity of his own — someone in front of a computer monitoring certain situations and hacking into things.
This is another good example. In this sequence of events, Prometheus was in complete control of things. He knew exactly where everyone was — it's why he was able to take down Ragman so easily. He also knew that Felicity was in trouble. Obviously Felicity was nearby so he could have heard it, but he seemed to know she was in trouble before he could have heard it. Oliver was nearby as well but couldn't hear that she was in trouble until Black Siren said her name. It seems the only way Prometheus could have known was if he had someone in his ear telling him about what was going on.
Now, we did see what appeared to be Prometheus's base of operation. It was seemingly low tech and there did not appear to be an area for a tech person.
Every Big Bad we have seen in Arrow has had considerable resources. Malcolm Merlyn was the leader of the Tempest (the people on the list) and he had a lot money that enabled him to pay people to do things for him. Slade Wilson also had money and a group of people that helped build an army. Ra's al Ghul had the entire League of Assassins behind him and Damien Darhk had H.I.V.E. supporting his agenda.
It seems that any major villain would need a strong support team to take on Team Arrow. The writers for Arrow have certainly gone out of their way to portray Prometheus's war on Oliver Queen as a largely one-man crusade. However, even with Evelyn on his side, it seems like he would need more resources to do everything he's done. How could one man piece together all the criminals that Oliver took down, track down the arrows that Oliver used, convert them into throwing stars, and recreate crime scenes all by himself? The process would be much easier for him if he had a tech person hacking into things and helping him out. After all, he is obsessed with Oliver Queen. If he were truly interested in taking him down, it would seem likely that he would have to rely on a similar model to that of Team Arrow.
One question remains: Who would be Prometheus's Felicity? In Arrow Episode 11, "Second Chances," Felicity met a very capable hacker that worked for an organization known as Helix, which has its roots in the comics.
It seems awfully coincidental for this random "Cojo Sledgehammer" woman to suddenly show up with information that could help free John Diggle. In the midseason finale, Prometheus appeared to be the one that set Diggle up. He sent Diggle a voicemail with Lila's voice calling for help, but how could he be able to fake her voice — the voice of the director of A.R.G.U.S. by himself? (Diggle said in "Second Chances" that Prometheus faked her voice, so let's assume it was orchestrated by Prometheus).
These events definitely appear to be related. Perhaps Prometheus found this woman at Helix and recruited her to help him out on his mission to take down Oliver Queen. Knowing Prometheus, he could also be threatening her and forcing her to help him. Prometheus's goal might be to get Felicity into something bad so that she will end up in trouble later on. He could have framed John Diggle in order to create a situation in which Felicity would suddenly become interested in going rogue. She clearly took the bait and opened Pandora's box (the files on the thumb drive the woman gave her were literally labeled "pandora"). Felicity is a crucial part of Team Arrow, and if she is compromised, Oliver will be much more vulnerable.
It would definitely be a cool storyline for Prometheus to have a Felicity of his own and this woman definitely seems like she could be his Felicity. It would certainly give him a leg up on Team Arrow.