In the final episode of Season 4, Donna has a revelation as she's standing waiting to pay for breakfast for her and Cameron. She looks from the people sat drinking and chatting, to the lady at the cash register, and the money in her hand, then rushes out to tell Cam: "I have an idea."

What do you think it is?

I had two thoughts:

1) an internet cafe - IRL Google tells me the first one was in 1994 - I can't remember what date the show gets up to, but it's probably mid 90s, right? The only issue with this, doesn't seem really like something a hardware and a software engineer would dream up, let alone create.

2) more likely, I think they could have been implying Donna had just struck upon the idea of cryptocurrency, or digital currency of some sort.

What do you reckon?

(PS>> can't believe they left Joe a Humanities lecturer. That is a kick in the teeth and probably the worst conclusion imaginable for the finest character in the show.)