I find it helpful to think of all nontrivial expenditures, income gains, etc., as (1) representative of a consistent "strategy" and (2) annualized. So when you choose to buy a latte, you should consider what general principle you're acting on (e.g., "have a latte every day", "have a latte on Monday mornings when thirsty and in a hurry", etc.) and then figure out what annual difference it will make. If you get a raise it's automatically annualized (though you should also think about its effects on your future salary, hireability, status, etc.). If you get a one-off bonus from your employer, you should consider it (something kinda like) equivalent to the annual income you can get from investing it. Etc.
(Of course you don't want to be doing this in detail every single time you make a decision with financial consequences. But if you get into the habit of thinking this way, your quick judgements will probably get better.)
That's a cool way to think about it.
Quick summary: "Hidden rationalists" are what I call authors who espouse rationalist principles, and probably think of themselves as rational people, but don't always write on "traditional" Less Wrong-ish topics and probably haven't heard of Less Wrong.
I've noticed that a lot of my rationalist friends seem to read the same ten blogs, and while it's great to have a core set of favorite authors, it's also nice to stretch out a bit and see how everyday rationalists are doing cool stuff in their own fields of expertise. I've found many people who push my rationalist buttons in fields of interest to me (journalism, fitness, etc.), and I'm sure other LWers have their own people in their own fields.
So I'm setting up this post as a place to link to/summarize the work of your favorite hidden rationalists. Be liberal with your suggestions!
Another way to phrase this: Who are the people/sources who give you the same feelings you get when you read your favorite LW posts, but who many of us probably haven't heard of?
Here's my list, to kick things off: