It may be in fact insecure to tell keyboard preferences in the public Forum. An addition to a good security practice.
I have stated before that my favorite (common) keyboard is the IBM/Lexmark/Unicomp Model M. That doesn't help you identify who I am at all, since there are hundreds of thousands of people preferring those keyboards. Even if you were physically in my office at work, or at my computer desk at home and saw the keyboard, you would not be able to infer who I am just from the keyboard. However, once you were in those locations, you would also be able to see my face, or read the street number of our house or the name on the office door, so identifying by keyboard is not adding any significant information.
A web browser can not read what type of keyboard I'm using. However, it could theoretically measure the timing of my key strokes. With enough data, a person might be indentifiable from that alone, but I doubt such a technique would have any appreciable accuracy, since the same person uses many different keyboards, and types in many different situations (an essay into a word processor / document preparation program is different from short lines into a chat, and different from coding). Their typing style also changes with time: caffeine yet? Did I do lots of physical labor (stacking concrete blocks, cutting down trees) yesterday and my hands are tired?
On the other hand, a web browser doesn't need to look at typing style to uniquely identify a person. They can just look at their web search preferences and sites they visit. This is a specific example of a very general problem: We all think that we have some privacy. For example, when I walk down the street in the shopping area of town, I think that nobody knows who I am. Nothing could be further from the truth. To begin with, I show my face, which can with very high accuracy be identified. To get there, I parked my car (with visible license plate), or perhaps I walked from my front door to the bus stop, then took the #123 bus to downtown. In reality, we have no privacy when we are in public, because we are easy to observe. And exactly the same applies on the web: the fact that I order things under my username JohnDoe on Amazon, and then visit the website of FirstAmalgamatedBank and look up the balance of account number 12345 tells the web browser very clearly who I am.
But we don't even need to go that far. If you know that I like using FreeBSD for my server, that my favorite chainsaw is the Stihl 260 followed by the Dolmar 7900, that I like to practice on a Bechstein but prefer to perform on the Boesendorfer Imperial, and drive a small orange-colored Honda, you have already uniquely identified me. I'm quite sure this is unique enough. If it isn't, add that I play my Bergerault vibes with DS19H mallets.
You consider that "alarming" and complain about "profiling". It is the reality, and has been since neanderthal times. It's called identity. Humans are unique, and it doesn't require much communication to authenticate their "fingerprint".
Never heard of this one before. What are you needing two mice for, except your machine is used by another person, and one is left handed, the other right handed, and if not, are you using them simultaneously (for a computer game, you're operating a robot arm while steering through 3D space?)? 
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(no need for on-OS software sending light patterns over USB)
