The "publon" is "the elementary quantum of scientific research which justifies publication" and it's also a website that might be interesting for you if you're an active researcher. Publons helps you collect records of your peer review activities. On this website, you can set up an account and then add your reviews to your profile page.You can decide whether you want to actually add the text of your reviews, or not, and to which level you want your reviews to be public. By default, only the journal for which you reviewed and the month during which the review was completed will be shown. So you need not be paranoid that people will know all the expletives you typed in reply to that idiot last year!
You don't even have to add the text of your review at all, you just have to provide a manuscript number. Your review activity is then checked against the records of the publisher, or so is my understanding.
Since I'm always interested in new community services, I set up an account there some months ago. It goes really quickly and is totally painless. You can then enter your review activities on the website or - super conveniently - you just forward the "Thank You" note from the publisher to some email address. The record then automatically appears on your profile within a day or two. I forwarded a bunch of "Thank You" emails from the last months, and now my profile page looks like follows:
The folks behind the website almost all have a background in academia and probably know it's pointless trying to make money from researchers. One expects of course that at some point they will try to monetize their site, but at least so far I have received zero spam, upgrade offers, or the dreaded newsletters that nobody wants to read.
In short, the site is doing exactly what it promises to do. I find the profile page really useful and will probably forward my other "Thank You" notes (to the extent that I can dig them up), and then put the link to that page in my CV and on my homepage.