In doing some work with Japanese, I’ve come across a Chrome browser extension called Mainichi which shows me a flashcard-like image and the related word in English and Japanese (with both associated kana) every time I open a new browser tab. Because I open dozens to hundreds of browser tabs a day it’s an easy way to review and even learn new words. (It also reminds me that I ought to be working on my next lesson instead of surfing the internet. 
)
I’m curious if anyone has seen anything like this for Welsh beyond the more focused use of flashcard technologies like Anki, Mnemosyne, et al?